git cl upload: die when --no-squash has no commit-msg-hook.

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 and Gerrit."""
 
 from distutils.version import LooseVersion
@@ skipping 2510 matching lines @@
     place.
     """
     log_desc = options.message or CreateDescriptionFromLog(args)
     git_command = ['commit', '--amend', '-m', log_desc]
     RunGit(git_command)
     new_log_desc = CreateDescriptionFromLog(args)
     if git_footers.get_footer_change_id(new_log_desc):
       print 'git-cl: Added Change-Id to commit message.'
       return new_log_desc
     else:
-      print >> sys.stderr, 'ERROR: Gerrit commit-msg hook not available.'
+      DieWithError('ERROR: Gerrit commit-msg hook not installed.')
 
   def SetCQState(self, new_state):
     """Sets the Commit-Queue label assuming canonical CQ config for Gerrit."""
     # TODO(tandrii): maybe allow configurability in codereview.settings or by
     # self-discovery of label config for this CL using REST API.
     vote_map = {
         _CQState.NONE:    0,
         _CQState.DRY_RUN: 1,
         _CQState.COMMIT : 2,
     }
@@ skipping 2345 matching lines @@
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   setup_color.init()
   try:
     sys.exit(main(sys.argv[1:]))
   except KeyboardInterrupt:
     sys.stderr.write('interrupted\n')
     sys.exit(1)