python3/plugins/test_extauth_hook_AD.py: Fix logging in run_cmd()

[bernhardkaindl]

Hi @psafont,
For logging the output of /usr/bin/systemctl reload-or-restart sshd in python3/plugins/extauth-hook-AD.py, mypy found a minor regression:

• We should add universal_newlines=True there to fix the formatting of the logged output.

How this could be found:

• mypy is good at spotting changes in str/bytes from moving to Python3
• mypy wasn't fully usable yet, the config was not yet updated for python3/*.
  • But with the moving of files to python3/* having made good process, I fixed the config for it.

In Python3, subprocess.check_output(command) returns bytes by default (unless it is switched to text mode).

• The original Python2 code assumes it returns str by default.
  • This leads to slightly non-ideal logging in this case.
• Fix this by using subprocess.check_output(command, universal_newlines=True)

The run_cmd function in python3/plugins/extauth-hook-AD.py has only one call:

       run_cmd(["/usr/bin/systemctl", "reload-or-restart", "sshd"])

Therefore, the unused default argument and returning the output can be removed (both are not used):

Commit 1:

• python3/plugins/test_extauth_hook_AD.py:
  • Assert the current bug and cover the to be fixed code.
  • No code change.

Commit 2:

• python3/plugins/extauth-hook-AD.py: Fix logging in run_cmd()
  • Fixes the bug and updates the test case
  • Simply the code and the test:
    • Remove the unused default argument log_cmd=True (cmd is always logged - only one call site)
    • Remove returning the command output (not used by the sole call site of this function)