Don't log if the job is already running - otherwise it spams cron.

infra/services/service_manager/__main__.py

 #!/usr/bin/env python
 # Copyright (c) 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import argparse
 import logging
 import signal
 import socket
 import sys
@@ skipping 56 matching lines @@
 
   def sigint_handler(_signal, _frame):
     watcher.stop()
 
   try:
     with daemon.flock('service_manager.flock', opts.state_directory):
       previous_sigint_handler = signal.signal(signal.SIGINT, sigint_handler)
       watcher.run()
       signal.signal(signal.SIGINT, previous_sigint_handler)
   except daemon.LockAlreadyLocked:
-    logging.error('Another instance of service_manager is already running')
+    # Another instance is already running.
     return 1
   else:
     ts_mon.close()
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))