Fix git try. git_try.py imports git_cl.py without calling its main.

git_cl.py

 #!/usr/bin/env python
 # Copyright (c) 2011 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."""
 
 import logging
@@ skipping 293 matching lines @@
 
 
 def ShortBranchName(branch):
   """Convert a name like 'refs/heads/foo' to just 'foo'."""
   return branch.replace('refs/heads/', '')
 
 
 class Changelist(object):
   def __init__(self, branchref=None):
     # Poke settings so we get the "configure your server" message if necessary.
+    global settings
+    if not settings:
+      # Happens when git_cl.py is used as a utility library.
+      settings = Settings()
     settings.GetDefaultServerUrl()
     self.branchref = branchref
     if self.branchref:
       self.branch = ShortBranchName(self.branchref)
     else:
       self.branch = None
     self.rietveld_server = None
     self.upstream_branch = None
     self.has_issue = False
     self.issue = None
@@ skipping 1088 matching lines @@
              'and retry or visit go/isgaeup.\n%s') % (e.code, str(e)))
 
   # Not a known command. Default to help.
   GenUsage(parser, 'help')
   return CMDhelp(parser, argv)
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   sys.exit(main(sys.argv[1:]))