Handle KeyboardInterrupt consistently in python scripts

roll_dep.py

 #!/usr/bin/env python
 # Copyright (c) 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.
 
 """This scripts takes the path to a dep and an svn revision, and updates the
 parent repo's DEPS file with the corresponding git revision.  Sample invocation:
 
 [chromium/src]$ roll-dep third_party/WebKit 12345
 
@@ skipping 380 matching lines @@
         'verification.' % revision)
     git_rev = revision
     comment = None
   else:
     (git_rev, svn_rev) = get_git_revision(dep_path, revision)
     comment = ('from svn revision %s' % svn_rev) if svn_rev else None
     assert git_rev, 'Could not find git revision matching %s.' % revision
   return update_deps(deps_file, dep_path, dep_name, git_rev, comment)
 
 if __name__ == '__main__':
-  sys.exit(main(sys.argv[1:]))
+  try:
+    sys.exit(main(sys.argv[1:]))
+  except KeyboardInterrupt:
+    sys.stderr.write('interrupted\n')
+    sys.exit(1)