fix(scanner): output all results even if all fail

[MaineK00n]

What did you implement:

When running vuls scan, there was a difference in behavior between cases where all servers failed and cases where only some servers failed in terms of generating results.
In this PR, we modify it to output results for all servers regardless of the situation.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

How Has This Been Tested?

In the display of the Scan Summary, you can confirm the generation of results.

all servers failed

before

$ vuls scan
[Mar  6 18:53:41]  INFO [localhost] vuls-v0.24.9-build-20240306_185212_bf14b5f
[Mar  6 18:53:41]  INFO [localhost] Start scanning
[Mar  6 18:53:41]  INFO [localhost] config: /home/mainek00n/github/github.com/MaineK00n/vuls/config.toml
[Mar  6 18:53:41]  INFO [localhost] Validating config...
[Mar  6 18:53:41]  INFO [localhost] Detecting Server/Container OS... 
[Mar  6 18:53:41]  INFO [localhost] Detecting OS of servers... 
[Mar  6 18:53:41] ERROR [localhost] (1/1) Failed: docker, err: [Failed to ssh-keyscan. cmd: /usr/bin/ssh-keyscan -p 2222 127.0.0.1, err:
    github.com/future-architect/vuls/scanner.validateSSHConfig
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:447
  - exit status 1]
[Mar  6 18:53:41] ERROR [localhost] Failed to scan: Failed to init servers. err:
    github.com/future-architect/vuls/scanner.Scanner.Scan
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:93
  - No scannable host OS:
    github.com/future-architect/vuls/scanner.Scanner.initServers
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:300

after

$ vuls scan
[Mar  6 18:50:16]  INFO [localhost] vuls-v0.24.9-build-20240306_184913_bf14b5f
[Mar  6 18:50:16]  INFO [localhost] Start scanning
[Mar  6 18:50:16]  INFO [localhost] config: /home/mainek00n/github/github.com/MaineK00n/vuls/config.toml
[Mar  6 18:50:16]  INFO [localhost] Validating config...
[Mar  6 18:50:16]  INFO [localhost] Detecting Server/Container OS... 
[Mar  6 18:50:16]  INFO [localhost] Detecting OS of servers... 
[Mar  6 18:50:16] ERROR [localhost] (1/1) Failed: docker, err: [Failed to ssh-keyscan. cmd: /usr/bin/ssh-keyscan -p 2222 127.0.0.1, err:
    github.com/future-architect/vuls/scanner.validateSSHConfig
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:447
  - exit status 1]
[Mar  6 18:50:16]  INFO [localhost] Detecting OS of containers... 
[Mar  6 18:50:16]  INFO [localhost] Checking Scan Modes... 
[Mar  6 18:50:16]  INFO [localhost] Detecting Platforms... 
[Mar  6 18:50:16]  WARN [localhost] Some warnings occurred during scanning on docker. Please fix the warnings to get a useful information. Execute configtest subcommand before scanning to know the cause of the warnings. warnings: [Failed to check EOL. Register the issue to https://github.com/future-architect/vuls/issues with the information in `Family:  Release: `]


Scan Summary
================
docker	Error		Use configtest subcommand or scan with --debug to view the details

Warning: [Failed to check EOL. Register the issue to https://github.com/future-architect/vuls/issues with the information in `Family:  Release: `]
[Mar  6 18:50:16] ERROR [localhost] Failed to scan: Failed to scan. err:
    github.com/future-architect/vuls/scanner.Scanner.Scan
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:110
  - An error occurred on [docker]

some servers failed

before

$ vuls scan
[Mar  6 18:54:43]  INFO [localhost] vuls-v0.24.9-build-20240306_185212_bf14b5f
[Mar  6 18:54:43]  INFO [localhost] Start scanning
[Mar  6 18:54:43]  INFO [localhost] config: /home/mainek00n/github/github.com/MaineK00n/vuls/config.toml
[Mar  6 18:54:43]  INFO [localhost] Validating config...
[Mar  6 18:54:43]  INFO [localhost] Detecting Server/Container OS... 
[Mar  6 18:54:43]  INFO [localhost] Detecting OS of servers... 
[Mar  6 18:54:43]  INFO [localhost] (1/2) Detected: pseudo: pseudo 
[Mar  6 18:54:43] ERROR [localhost] (2/2) Failed: docker, err: [Failed to ssh-keyscan. cmd: /usr/bin/ssh-keyscan -p 2222 127.0.0.1, err:
    github.com/future-architect/vuls/scanner.validateSSHConfig
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:447
  - exit status 1]
[Mar  6 18:54:43]  INFO [localhost] Detecting OS of containers... 
[Mar  6 18:54:43]  INFO [localhost] Checking Scan Modes... 
[Mar  6 18:54:43]  INFO [localhost] Detecting Platforms... 
[Mar  6 18:54:43]  INFO [localhost] (1/1) pseudo is running on other
[Mar  6 18:54:43]  INFO [pseudo] Scanning listen port...
[Mar  6 18:54:43]  INFO [pseudo] Using Port Scanner: Vuls built-in Scanner
[Mar  6 18:54:43]  WARN [localhost] Some warnings occurred during scanning on docker. Please fix the warnings to get a useful information. Execute configtest subcommand before scanning to know the cause of the warnings. warnings: [Failed to check EOL. Register the issue to https://github.com/future-architect/vuls/issues with the information in `Family:  Release: `]


Scan Summary
================
pseudo	pseudo	0 installed, 0 updatable
docker	Error 	                        	Use configtest subcommand or scan with --debug to view the details

Warning: [Failed to check EOL. Register the issue to https://github.com/future-architect/vuls/issues with the information in `Family:  Release: `]
[Mar  6 18:54:43] ERROR [localhost] Failed to scan: Failed to scan. err:
    github.com/future-architect/vuls/scanner.Scanner.Scan
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:110
  - An error occurred on [docker]

after

$ vuls scan
[Mar  6 18:57:37]  INFO [localhost] vuls-v0.24.9-build-20240306_185559_bf01495
[Mar  6 18:57:37]  INFO [localhost] Start scanning
[Mar  6 18:57:37]  INFO [localhost] config: /home/mainek00n/github/github.com/MaineK00n/vuls/config.toml
[Mar  6 18:57:37]  INFO [localhost] Validating config...
[Mar  6 18:57:37]  INFO [localhost] Detecting Server/Container OS... 
[Mar  6 18:57:37]  INFO [localhost] Detecting OS of servers... 
[Mar  6 18:57:37]  INFO [localhost] (1/2) Detected: pseudo: pseudo 
[Mar  6 18:57:37] ERROR [localhost] (2/2) Failed: docker, err: [Failed to ssh-keyscan. cmd: /usr/bin/ssh-keyscan -p 2222 127.0.0.1, err:
    github.com/future-architect/vuls/scanner.validateSSHConfig
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:447
  - exit status 1]
[Mar  6 18:57:37]  INFO [localhost] Detecting OS of containers... 
[Mar  6 18:57:37]  INFO [localhost] Checking Scan Modes... 
[Mar  6 18:57:37]  INFO [localhost] Detecting Platforms... 
[Mar  6 18:57:37]  INFO [localhost] (1/1) pseudo is running on other
[Mar  6 18:57:37]  INFO [pseudo] Scanning listen port...
[Mar  6 18:57:37]  INFO [pseudo] Using Port Scanner: Vuls built-in Scanner
[Mar  6 18:57:37]  WARN [localhost] Some warnings occurred during scanning on docker. Please fix the warnings to get a useful information. Execute configtest subcommand before scanning to know the cause of the warnings. warnings: [Failed to check EOL. Register the issue to https://github.com/future-architect/vuls/issues with the information in `Family:  Release: `]


Scan Summary
================
pseudo	pseudo	0 installed, 0 updatable
docker	Error 	                        	Use configtest subcommand or scan with --debug to view the details

Warning: [Failed to check EOL. Register the issue to https://github.com/future-architect/vuls/issues with the information in `Family:  Release: `]
[Mar  6 18:57:37] ERROR [localhost] Failed to scan: Failed to scan. err:
    github.com/future-architect/vuls/scanner.Scanner.Scan
        /home/mainek00n/github/github.com/MaineK00n/vuls/scanner/scanner.go:110
  - An error occurred on [docker]

Checklist:

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• Write documentation
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Is this ready for review?: YES

Reference

[shino]

Fooray!!