Fix auto-roll configuration.

tools/push-to-trunk/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 json
 import os
 import sys
 import urllib
 
 from common_includes import *
 import chromium_roll
 
+CONFIG = {
+  PERSISTFILE_BASENAME: "/tmp/v8-auto-roll-tempfile",
+}
+
 CR_DEPS_URL = 'http://src.chromium.org/svn/trunk/src/DEPS'
 
 class CheckActiveRoll(Step):
   MESSAGE = "Check active roll."
 
   @staticmethod
   def ContainsChromiumRoll(changes):
     for change in changes:
       if change["subject"].startswith("Update V8 to"):
         return True
@@ skipping 73 matching lines @@
     return [
       CheckActiveRoll,
       DetectLastPush,
       DetectLastRoll,
       RollChromium,
     ]
 
 
 if __name__ == "__main__":  # pragma: no cover
   sys.exit(AutoRoll(CONFIG).Run())