Abort `git cl push` if pushing into a local branch.

tests/git_cl_test.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.
 
 """Unit tests for git_cl.py."""
 
 import os
 import StringIO
 import stat
@@ skipping 252 matching lines @@
       ((['git', 'symbolic-ref', 'HEAD'],), 'refs/heads/working'),
       ((['git', 'config', '--int', '--get',
         'branch.working.git-cl-similarity'],), ''),
       ((['git', 'symbolic-ref', 'HEAD'],), 'refs/heads/working'),
       ((['git', 'config', '--int', '--get',
         'branch.working.git-find-copies'],), ''),
       ((['git', 'symbolic-ref', 'HEAD'],), 'refs/heads/working'),
       ((['git',
          'config', 'branch.working.merge'],), 'refs/heads/master'),
       ((['git', 'config', 'branch.working.remote'],), 'origin'),
+      ((['git', 'config', 'branch.working.merge'],),
+       'refs/heads/master'),
+      ((['git', 'config', 'branch.working.remote'],), 'origin'),
       ((['git', 'rev-list', '--merges',
          '--grep=^SVN changes up to revision [0-9]*$',
          'refs/remotes/origin/master^!'],), ''),
       ((['git', 'update-index', '--refresh', '-q'],), ''),
       ((['git', 'diff-index', '--name-status', 'HEAD'],), ''),
       ((['git', 'rev-list', '^refs/heads/working',
          'refs/remotes/origin/master'],),
          ''),
       ((['git',
          'log', '--grep=^git-svn-id:', '-1', '--pretty=format:%H'],),
@@ skipping 458 matching lines @@
       obj = git_cl.ChangeDescription(orig)
       obj.update_reviewers(reviewers)
       actual.append(obj.description)
     self.assertEqual(expected, actual)
 
 
 if __name__ == '__main__':
   git_cl.logging.basicConfig(
       level=git_cl.logging.DEBUG if '-v' in sys.argv else git_cl.logging.ERROR)
   unittest.main()