Change usage of deprecated flag.

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 __future__ import print_function
@@ skipping 1357 matching lines @@
     # We use the sha1 of HEAD as a name of this change.
     name = RunGitWithCode(['rev-parse', 'HEAD'])[1].strip()
     # Need to pass a relative path for msysgit.
     try:
       files = scm.GIT.CaptureStatus([root], '.', upstream_branch)
     except subprocess2.CalledProcessError:
       DieWithError(
           ('\nFailed to diff against upstream branch %s\n\n'
            'This branch probably doesn\'t exist anymore. To reset the\n'
            'tracking branch, please run\n'
-           '    git branch --set-upstream %s trunk\n'
-           'replacing trunk with origin/master or the relevant branch') %
+           '    git branch --set-upstream-to origin/master %s\n'
+           'or replace origin/master with the relevant branch') %
           (upstream_branch, self.GetBranch()))
 
     issue = self.GetIssue()
     patchset = self.GetPatchset()
     if issue and not local_description:
       description = self.GetDescription()
     else:
       # If the change was never uploaded, use the log messages of all commits
       # up to the branch point, as git cl upload will prefill the description
       # with these log messages.
@@ skipping 3472 matching lines @@
 def CMDupstream(parser, args):
   """Prints or sets the name of the upstream branch, if any."""
   _, args = parser.parse_args(args)
   if len(args) > 1:
     parser.error('Unrecognized args: %s' % ' '.join(args))
 
   cl = Changelist()
   if args:
     # One arg means set upstream branch.
     branch = cl.GetBranch()
-    RunGit(['branch', '--set-upstream', branch, args[0]])
+    RunGit(['branch', '--set-upstream-to', args[0], branch])
     cl = Changelist()
     print('Upstream branch set to %s' % (cl.GetUpstreamBranch(),))
 
     # Clear configured merge-base, if there is one.
     git_common.remove_merge_base(branch)
   else:
     print(cl.GetUpstreamBranch())
   return 0
 
 
@@ skipping 413 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)