Handle KeyboardInterrupt consistently in python scripts

git_rebase_update.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.
 
 """
 Tool to update all branches to have the latest changes from their upstreams.
 """
 
 import argparse
@@ skipping 169 matching lines @@
           return False
   else:
     print '%s up-to-date' % branch
 
   git.remove_merge_base(branch)
   git.get_or_create_merge_base(branch)
 
   return True
 
 
-def main(args=()):
+def main(args=None):
   parser = argparse.ArgumentParser()
   parser.add_argument('--verbose', '-v', action='store_true')
   parser.add_argument('--no_fetch', '--no-fetch', '-n',
                       action='store_true',
                       help='Skip fetching remotes.')
   opts = parser.parse_args(args)
 
   if opts.verbose:  # pragma: no cover
     logging.getLogger().setLevel(logging.DEBUG)
 
@@ skipping 62 matching lines @@
           "%r was merged with its parent, checking out %r instead."
           % (return_branch, root_branch)
         )
       git.run('checkout', root_branch)
     git.set_config(STARTING_BRANCH_KEY, '')
 
   return retcode
 
 
 if __name__ == '__main__':  # pragma: no cover
-  sys.exit(main(sys.argv[1:]))
+  try:
+    sys.exit(main())
+  except KeyboardInterrupt:
+    sys.stderr.write('interrupted\n')
+    sys.exit(1)