Fix git cl comments when there's no issue associated with the current branch.

git_cl.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld."""
 
 from distutils.version import LooseVersion
@@ skipping 1444 matching lines @@
     except ValueError:
       DieWithError('A review issue id is expected to be a number')
 
   cl = Changelist(issue=issue)
 
   if options.comment:
     cl.AddComment(options.comment)
     return 0
 
   data = cl.GetIssueProperties()
-  for message in sorted(data['messages'], key=lambda x: x['date']):
+  for message in sorted(data.get('messages', []), key=lambda x: x['date']):
     if message['disapproval']:
       color = Fore.RED
     elif message['approval']:
       color = Fore.GREEN
     elif message['sender'] == data['owner_email']:
       color = Fore.MAGENTA
     else:
       color = Fore.BLUE
     print '\n%s%s  %s%s' % (
         color, message['date'].split('.', 1)[0], message['sender'],
@@ skipping 1411 matching lines @@
         ('AppEngine is misbehaving and returned HTTP %d, again. Keep faith '
           'and retry or visit go/isgaeup.\n%s') % (e.code, str(e)))
 
 
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   colorama.init()
   sys.exit(main(sys.argv[1:]))