[Release] Update merge script to leverage auto-tag bot

tools/release/roll_merge.py

 #!/usr/bin/env python
 # Copyright 2014 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 202 matching lines @@
 
   def RunStep(self):
     self.CommonCleanup()
     print "*** SUMMARY ***"
     print "version: %s" % self["version"]
     print "branch: %s" % self["merge_to_branch"]
     if self["revision_list"]:
       print "patches: %s" % self["revision_list"]
 
 
-class MergeToBranch(ScriptsBase):
+class RollMerge(ScriptsBase):
   def _Description(self):
     return ("Performs the necessary steps to merge revisions from "
-            "master to other branches, including candidates.")
+            "master to other branches, including candidates and roll branches.")
 
   def _PrepareOptions(self, parser):
     group = parser.add_mutually_exclusive_group(required=True)
     group.add_argument("--branch", help="The branch to merge to.")
     parser.add_argument("revisions", nargs="*",
                         help="The revisions to merge.")
     parser.add_argument("-f", "--force",
                         help="Delete sentinel file.",
                         default=False, action="store_true")
     parser.add_argument("-m", "--message",
@@ skipping 43 matching lines @@
       IncrementVersion,
       CommitLocal,
       UploadStep,
       CommitRepository,
       TagRevision,
       CleanUp,
     ]
 
 
 if __name__ == "__main__":  # pragma: no cover
-  sys.exit(MergeToBranch().Run())
+  sys.exit(RollMerge().Run())