Catch SIGTERM and raise SystemExit in submanager

This allow submanager to do some cleanup when it receive sigterm
(in this case removing pid file and killing subprocess).

slapos/submanager.py

@@ -136,6 +136,9 @@ def usr1_handler(signum, frame):
   if PROCESS.restarting is False:
     PROCESS.restart()
 
+def term_handler(signum, frame):
+  raise SystemExit
+
 def main():
   global PROCESS
 
@@ -151,6 +154,8 @@ def main():
 
   args = parser.parse_args()
 
+  signal.signal(signal.SIGTERM, term_handler)
+
   if args.pidfile is not None:
     with open(args.pidfile, 'w') as pid_file:
       pid_file.write('%d' % os.getpid())