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

tools/release/roll_merge.py

Index: tools/release/roll_merge.py
diff --git a/tools/release/merge_to_branch.py b/tools/release/roll_merge.py
similarity index 98%
copy from tools/release/merge_to_branch.py
copy to tools/release/roll_merge.py
index 699fe1b3c66dbc5fc67970616eb811136ecad844..2dd43eae3ac25b1fcd03f919e4dbc4b19b2338e4 100755
--- a/tools/release/merge_to_branch.py
+++ b/tools/release/roll_merge.py
@@ -220,10 +220,10 @@ class CleanUp(Step):
       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)
@@ -287,4 +287,4 @@ class MergeToBranch(ScriptsBase):
 
 
 if __name__ == "__main__":  # pragma: no cover
-  sys.exit(MergeToBranch().Run())
+  sys.exit(RollMerge().Run())