Skip apply_gerrit rebase when there is a rebase failure

recipe_modules/bot_update/resources/bot_update.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 # TODO(hinoka): Use logging.
 
 import cStringIO
 import codecs
 import collections
@@ skipping 586 matching lines @@
     git('retry', 'fetch', gerrit_repo, gerrit_ref, cwd=root, tries=1)
     git('checkout', 'FETCH_HEAD', cwd=root)
 
     if gerrit_rebase_patch_ref:
       print '===Rebasing==='
       # git rebase requires a branch to operate on.
       temp_branch_name = 'tmp/' + uuid.uuid4().hex
       try:
         ok = False
         git('checkout', '-b', temp_branch_name, cwd=root)
-        git('rebase', base_rev, cwd=root)
+        try:
+          git('rebase', base_rev, cwd=root)
+        except SubprocessFailed:
+          # Abort the rebase since there were failures.
+          git('rebase', '--abort', cwd=root)
+          raise
 
         # Get off of the temporary branch since it can't be deleted otherwise.
         cur_rev = git('rev-parse', 'HEAD', cwd=root).strip()
         git('checkout', cur_rev, cwd=root)
         git('branch', '-D', temp_branch_name, cwd=root)
         ok = True
       finally:
         if not ok:
           # Get off of the temporary branch since it can't be deleted otherwise.
           git('checkout', base_rev, cwd=root)
@@ skipping 442 matching lines @@
     # download patch failure is still an infra problem.
     if e.code == 3:
       # Patch download problem.
       return 87
     # Genuine patch problem.
     return 88
 
 
 if __name__ == '__main__':
   sys.exit(main())