Make testing/buildbot presubmit output less mysterious.

testing/buildbot/manage.py

 #!/usr/bin/env python
 # Copyright 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.
 
 """Toolbox to manage all the json files in this directory.
 
 It can reformat them in their canonical format or ensures they are well
 formatted.
 """
@@ skipping 127 matching lines @@
         config, sort_keys=True, indent=2, separators=(',', ': ')) + '\n'
     if content != expected:
       result = 1
       if args.write or args.convert:
         with open(filepath, 'wb') as f:
           f.write(expected)
         if args.write:
           print('Updated %s' % filename)
       else:
         print('%s is not in canonical format' % filename)
+        print('run `testing/buildbot/manage.py -w` to fix')
 
   if args.remaining:
     if args.test_name:
       if args.test_name not in tests_location:
         print('Unknown test %s' % args.test_name)
         return 1
       for config, builders in sorted(
           tests_location[args.test_name]['local_configs'].iteritems()):
         print('%s:' % config)
         for builder in sorted(builders):
@@ skipping 26 matching lines @@
       p_swarming = 100. * total_swarming / total
       print('%s%-*s %4d (%4.1f%%)   %4d (%4.1f%%)' %
           (colorama.Fore.WHITE, l, 'Total:', total_local, p_local,
             total_swarming, p_swarming))
       print('%-*s                %4d' % (l, 'Total executions:', total))
   return result
 
 
 if __name__ == "__main__":
   sys.exit(main())