Make rebase and sync the default for Gerrit updates

recipe_modules/bot_update/resources/apply_gerrit.py

 #!/usr/bin/env python
 # Copyright 2016 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.
 
 import optparse
 import sys
 
 import bot_update  # pylint: disable=relative-import
 
 
 if __name__ == '__main__':
   parse = optparse.OptionParser()
 
   parse.add_option('--gerrit_repo',
                    help='Gerrit repository to pull the ref from.')
   parse.add_option('--gerrit_ref', help='Gerrit ref to apply.')
   parse.add_option('--root', help='The location of the checkout.')
   parse.add_option('--gerrit_no_reset', action='store_true',
                    help='Bypass calling reset after applying a gerrit ref.')
-  parse.add_option('--gerrit_rebase_patch_ref', action='store_true',
-                   help='Rebase Gerrit patch ref after of checking it out.')
+  parse.add_option('--gerrit_no_rebase_patch_ref', action='store_true',
+                   help='Bypass rebase of Gerrit patch ref after checkout.')
 
   options, _ = parse.parse_args()
 
   sys.exit(
       bot_update.apply_gerrit_ref(
           options.gerrit_repo,
           options.gerrit_ref,
           options.root,
           not options.gerrit_no_reset,
-          options.gerrit_rebase_patch_ref)
+          not options.gerrit_no_rebase_patch_ref)
   )