Re-open lock file before locking

because the previous 'withlock' cleanup function might have deleted
the file and since we still held a handle to the old deleted file,
we could run concurrently with a 3rd 'withlock' which creates a new file.

Fixes poeml#1
Fixes boo#864785

Signed-off-by: Bernhard M. Wiedemann <bwiedemann@suse.de>

withlock

@@ -137,12 +137,11 @@ def main():
 
     prev_umask = os.umask(0o066)
 
-    lock = open(lockfile, 'w')
-
     global got_lock
     while 1 + 1 == 2:
 
         try:
+            lock = open(lockfile, 'w')
             fcntl.lockf(lock, fcntl.LOCK_EX | fcntl.LOCK_NB)
             got_lock = True
             break