Add more logging to builder_alerts to see why metrics are not reported

infra/services/builder_alerts/__main__.py

 #!/usr/bin/env python
 # Copyright 2014 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 contextlib
 import cStringIO
 import datetime
 import gzip
@@ skipping 409 matching lines @@
         _ConnectionpoolFilter())
 
   def outer_loop_iteration():
     return inner_loop(args)
 
   loop_results = outer_loop.loop(
       task=outer_loop_iteration,
       sleep_timeout=lambda: 5,
       **loop_args)
 
+  logging.debug('Flushing ts_mon starting')
   ts_mon.flush()
+  logging.debug('Flushing ts_mon completed')
   return 0 if loop_results.success else 1
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))