Handle KeyboardInterrupt consistently in python scripts

git_rename_branch.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.
 
 """Rename the current branch while maintaining correct dependencies."""
 
 import argparse
 import sys
 
@@ skipping 26 matching lines @@
 
     # update the downstreams
     for branch, merge in branch_config_map('merge').iteritems():
       if merge == 'refs/heads/' + opts.old_name:
         # Only care about local branches
         if branch_config(branch, 'remote') == '.':
           set_branch_config(branch, 'merge', 'refs/heads/' + opts.new_name)
   except subprocess2.CalledProcessError as cpe:
     sys.stderr.write(cpe.stderr)
     return 1
+  return 0
 
 
 if __name__ == '__main__':  # pragma: no cover
-  sys.exit(main(sys.argv[1:]))
+  try:
+    sys.exit(main(sys.argv[1:]))
+  except KeyboardInterrupt:
+    sys.stderr.write('interrupted\n')
+    sys.exit(1)