There is a possibility that we jump onto error label with @lockpath
still initialized to NULL. Here, the @lockpath should be unlink()-ed,
but passing there a NULL is not a good idea. Don't do that. In fact,
we should call unlink() only if we created the lock file successfully.
Reported-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>