Fix creds error

[space-r7]

Calling creds when core.private is nil results in a crash. The fix was made prior to calling reload_lib in the output below.

Related: #11433

msf5 > creds
[-] Error while running command creds: undefined method `jtr_format' for nil:NilClass

Call stack:
/Users/space/metasploit-framework/lib/msf/ui/console/command_dispatcher/creds.rb:474:in `block in creds_search'
/Users/space/.rvm/gems/ruby-2.6.2@metasploit-framework/gems/activerecord-4.2.11.1/lib/active_record/relation/delegation.rb:46:in `each'
/Users/space/.rvm/gems/ruby-2.6.2@metasploit-framework/gems/activerecord-4.2.11.1/lib/active_record/relation/delegation.rb:46:in `each'
/Users/space/metasploit-framework/lib/msf/ui/console/command_dispatcher/creds.rb:441:in `creds_search'
/Users/space/metasploit-framework/lib/msf/ui/console/command_dispatcher/creds.rb:112:in `cmd_creds'
/Users/space/metasploit-framework/lib/rex/ui/text/dispatcher_shell.rb:523:in `run_command'
/Users/space/metasploit-framework/lib/rex/ui/text/dispatcher_shell.rb:474:in `block in run_single'
/Users/space/metasploit-framework/lib/rex/ui/text/dispatcher_shell.rb:468:in `each'
/Users/space/metasploit-framework/lib/rex/ui/text/dispatcher_shell.rb:468:in `run_single'
/Users/space/metasploit-framework/lib/rex/ui/text/shell.rb:151:in `run'
/Users/space/metasploit-framework/lib/metasploit/framework/command/console.rb:48:in `start'
/Users/space/metasploit-framework/lib/metasploit/framework/command/base.rb:82:in `start'
./msfconsole:49:in `<main>'
msf5 > reload_lib lib/msf/ui/console/command_dispatcher/creds.rb
[*] Reloading /Users/space/metasploit-framework/lib/msf/ui/console/command_dispatcher/creds.rb
msf5 > creds
Credentials
===========

host            origin          service         public       private                                                       realm  private_type        JtR Format
----            ------          -------         ------       -------                                                       -----  ------------        ----------
                192.168.37.246                  secondUser                                                                                            
                                                blah         blahpassword                                                         Password   

[wvu]

msf5 > creds add user:space
msf5 > creds
[-] Error while running command creds: undefined method `jtr_format' for nil:NilClass

Call stack:
/rapid7/metasploit-framework/lib/msf/ui/console/command_dispatcher/creds.rb:474:in `block in creds_search'
/Users/wvu/.rbenv/versions/2.6.2/lib/ruby/gems/2.6.0/gems/activerecord-4.2.11.1/lib/active_record/relation/delegation.rb:46:in `each'
/Users/wvu/.rbenv/versions/2.6.2/lib/ruby/gems/2.6.0/gems/activerecord-4.2.11.1/lib/active_record/relation/delegation.rb:46:in `each'
/rapid7/metasploit-framework/lib/msf/ui/console/command_dispatcher/creds.rb:441:in `creds_search'
/rapid7/metasploit-framework/lib/msf/ui/console/command_dispatcher/creds.rb:112:in `cmd_creds'
/rapid7/metasploit-framework/lib/rex/ui/text/dispatcher_shell.rb:523:in `run_command'
/rapid7/metasploit-framework/lib/rex/ui/text/dispatcher_shell.rb:474:in `block in run_single'
/rapid7/metasploit-framework/lib/rex/ui/text/dispatcher_shell.rb:468:in `each'
/rapid7/metasploit-framework/lib/rex/ui/text/dispatcher_shell.rb:468:in `run_single'
/rapid7/metasploit-framework/lib/rex/ui/text/shell.rb:151:in `run'
/rapid7/metasploit-framework/lib/metasploit/framework/command/console.rb:48:in `start'
/rapid7/metasploit-framework/lib/metasploit/framework/command/base.rb:82:in `start'
./msfconsole:49:in `<main>'
msf5 >

[wvu]

msf5 > creds add user:space
msf5 > creds
Credentials
===========

host  origin  service  public  private  realm  private_type  JtR Format
----  ------  -------  ------  -------  -----  ------------  ----------
                       space

msf5 >

[wvu]

Release Notes

This fixes a crash in the creds command when a credential doesn't have a private object associated with it.

[jmartin-tech]

Added msf5 as jtr overhaul is currently not in 4.x