Have git-cl try fail when used on a closed CL

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 2285 matching lines @@
   options, args = parser.parse_args(args)
 
   if args:
     parser.error('Unknown arguments: %s' % args)
 
   cl = Changelist()
   if not cl.GetIssue():
     parser.error('Need to upload first')
 
   props = cl.GetIssueProperties()
+  if props.get('closed'):
+    parser.error('Cannot send tryjobs for a closed CL')
+
   if props.get('private'):
     parser.error('Cannot use trybots with private issue')
 
   if not options.name:
     options.name = cl.GetBranch()
 
   if options.bot and not options.master:
     options.master, err_msg = GetBuilderMaster(options.bot)
     if err_msg:
       parser.error('Tryserver master cannot be found because: %s\n'
@@ skipping 354 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:]))