[Android] Fix uirobot --minutes help text in test_runner.py

build/android/test_runner.py

 #!/usr/bin/env python
 #
 # Copyright 2013 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.
 
 """Runs all types of tests from one unified interface."""
 
 import argparse
 import collections
@@ skipping 511 matching lines @@
       args.extra_args)
 
 def AddUirobotTestOptions(parser):
   """Adds uirobot test options to |option_parser|."""
   group = parser.add_argument_group('Uirobot Test Options')
 
   group.add_argument('--app-under-test', required=True,
                      help='APK to run tests on.')
   group.add_argument(
       '--minutes', default=5, type=int,
-      help='Number of minutes to run uirobot test [default: %default].')
+      help='Number of minutes to run uirobot test [default: %(default)s].')
 
   AddCommonOptions(parser)
   AddDeviceOptions(parser)
   AddRemoteDeviceOptions(parser)
 
 def AddPerfTestOptions(parser):
   """Adds perf test options to |parser|."""
 
   group = parser.add_argument_group('Perf Test Options')
 
@@ skipping 466 matching lines @@
     subparser = command_parsers.add_parser(
         test_type, usage='%(prog)s [options]', help=config.help_txt)
     config.add_options_func(subparser)
 
   args = parser.parse_args()
   return RunTestsCommand(args, parser)
 
 
 if __name__ == '__main__':
   sys.exit(main())