Send logs from wpa_supplicant action to the journal

[albertvaka]

The logs from the action script passed to wpa_supplicant end in /dev/null by default when wpa_supplicant runs in daemon mode. This redirects them to the journal instead.

[joukewitteveen]

I see the appeal, but will need some more convincing since I dislike the looks of this change. The identifier is new and does not link back to netctl, and merging stderr and stdout is a bad idea. Maybe we should see whether wpa_supplicant can support yielding its stdout/stderr to the action scripts.

[albertvaka]

I agree this is not great and that it would be better fixed on the wpa_supplicant side, unfortunately I don't have the time to pursue a fix there. I still posted this PR because this is how I found #193 so it has proven quite a useful workaround already, and I also wanted to call your attention onto the problem of the output disappear into the ether. Feel free to close and maybe open an issue instead?

[joukewitteveen]

If I have time again, I want to investigate whether we can hook up the output to the journal in such a way that it becomes visible in systemctl status netctl-auto@INTERFACE. Perhaps for stderr we could have a separate redirect that somehow makes it clear we are dealing with errors.

[albertvaka]

Splitting the stdout and stderr should be easy:

exec > >(systemd-cat -t wpa_action -p info) \
     2> >(systemd-cat -t wpa_action -p err)

But with this mechanism you can't make it part of the existing systemd unit's logs.