This is an alternative to the fix made in 3b52909f which removed the
chown call entirely.

Prior to 3b52909f, the ownership of $PID_FOLDER was always changed even
when its value was /var/run. This was problematic as it could prevent
other services from creating their pid folder or file.

When a sub-folder is used, changing its ownership so that it’s owned by
the user that will run the app is desirable as it limits access to the
folder. Rather than removing the chown call entirely, this commit
ensures that it only happens when a sub-folder is being used to hold the
pid file.

Closes gh-6532