[email protected]: do not exit as error when preventing restart

[valentindavid]

Upstreaming of canonical/core-base#296

This does not affect behavior apart from systemctl not showing the service in red.

[dbungert]

Thanks Valentin.

I have a question - I'm looking at this combination and it seems a little unexpected

RestartPreventExitStatus=22
SuccessExitStatus=22
Restart=always

We're deliberately using exit 22 as success (fine) and not restarting with that (fine), but that means that an exit 0 would be a restart while exit 22 would not restart, is this intended?

I wonder if we instead want this, which means an exit 0 doesn't restart and we don't need RestartPreventExitStatus. Thoughts?

SuccessExitStatus=22
Restart=on-failure