[release] Fix auto-roller.

tools/release/auto_roll.py

 #!/usr/bin/env python
 # Copyright 2014 the V8 project 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 argparse
 import os
 import sys
 
 from common_includes import *
@@ skipping 105 matching lines @@
 
 
 class UpdateChromiumCheckout(Step):
   MESSAGE = "Update the checkout and create a new branch."
 
   def RunStep(self):
     self['json_output']['monitoring_state'] = 'update_chromium'
     cwd = self._options.chromium
     self.GitCheckout("master", cwd=cwd)
     self.DeleteBranch("work-branch", cwd=cwd)
-    self.Command("gclient", "sync --nohooks", cwd=cwd)
     self.GitPull(cwd=cwd)
 
     # Update v8 remotes.
     self.GitFetchOrigin()
 
     self.GitCreateBranch("work-branch", cwd=cwd)
 
 
 class UploadCL(Step):
   MESSAGE = "Create and upload CL."
@@ skipping 83 matching lines @@
       PrepareRollCandidate,
       SwitchChromium,
       UpdateChromiumCheckout,
       UploadCL,
       CleanUp,
     ]
 
 
 if __name__ == "__main__":  # pragma: no cover
   sys.exit(AutoRoll().Run())