Fix flaky set_computer_name in mac_system module

[dwoz]

What does this PR do?

Use scutil instead of systemsetup to set and get the computer name on MacOS. systemsetup is from 2002 and is not reliable at setting the computer name.

(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -setcomputername "RS-KFQZY1"
setcomputername: RS-KFQZY1
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -getcomputername
Computer Name: RS-KFQZYP
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -getcomputername
Computer Name: RS-KFQZYP
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -getcomputername
Computer Name: RS-KFQZYP
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -getcomputername
Computer Name: RS-KFQZYP
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -getcomputername
Computer Name: RS-KFQZYP
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -setcomputername "RS-KFQZY1"
setcomputername: RS-KFQZY1
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -getcomputername
Computer Name: RS-KFQZYP
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -getcomputername
Computer Name: RS-KFQZYP
(venv) root@carbon:~/src/salt-forge/2019.2.1-tests/salt# systemsetup -getcomputername
Computer Name: RS-KFQZYP

scutil is from 2008 and scutil --set ComputerName "RS-KFQZY1" works reliably.

Tests written?

No - Has existing test coverage that was failing

Commits signed with GPG?

Yes

[Ch3LL]

Great find! I think there are other modules that use systemsetup as well that are flaky. That command is just flaky in general so might be good to switch to a different command if available in those modules too if they keep failing in the future. The other modules are mac_timezone.py and mac_power.py

[dwoz]

Great find! I think there are other modules that use systemsetup as well that are flaky. That command is just flaky in general so might be good to switch to a different command if available in those modules too if they keep failing in the future. The other modules are mac_timezone.py and mac_power.py

I agree.