Fix candidate lookup in auto push script.

tools/push-to-trunk/auto_push.py

 #!/usr/bin/env python
 # Copyright 2013 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
@@ skipping 57 matching lines @@
     if re.search(r"nopush|no push", self["tree_message"], flags=re.I):
       self.Die("Push to trunk disabled by tree state: %s"
                % self["tree_message"])
 
 
 class FetchCandidate(Step):
   MESSAGE = "Fetching V8 roll candidate ref."
 
   def RunStep(self):
     self.Git("fetch origin +refs/heads/candidate:refs/heads/candidate")
-    self["candidate"] = self.Git("show-ref -s refs/heads/candidate")
+    self["candidate"] = self.Git("show-ref -s refs/heads/candidate").strip()
 
 
 class CheckLastPush(Step):
   MESSAGE = "Checking last V8 push to trunk."
 
   def RunStep(self):
     last_push = self.FindLastTrunkPush()
 
     # Retrieve the bleeding edge revision of the last push from the text in
     # the push commit message.
@@ skipping 55 matching lines @@
       CheckAutoPushSettings,
       CheckTreeStatus,
       FetchCandidate,
       CheckLastPush,
       PushToCandidates,
     ]
 
 
 if __name__ == "__main__":  # pragma: no cover
   sys.exit(AutoPush().Run())