pid file locking in pylockfile fails to handle stale PID

[Tim Wright]

The Python python-daemon library (https://pagure.io/python-daemon) leverages pylockfile to implement
the pidfile functionality for daemons. Unfortunately, the pidfile code in pylockfile fails to check
if the PID is alive and so it erroneously fails if the daemon dies, or the node crashes, or anything
else happens that causes the process to die, but the pid file to not be cleaned up.

I see from the main page that this package is marked as deprecated. The suggested replacement packages
have no equivalent functionality for the pidfile code. If you are willing to take a patch to fix the
pidfile functionality, I would be happy to provide one.

[Ben Nemec (bnemec)]

I'm afraid we've retired our version of pylockfile, so there's nowhere for us to apply a patch. At this point I think we'd rather add the required functionality to fasteners, if that's possible.