merger.rb: runnable

* tool/merger.rb: make runnable.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39425 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/merger.rb

@@ -1,4 +1,7 @@
-#! /bin/ruby
+#!/bin/sh
+# -*- ruby -*-
+exec "${RUBY-ruby}" "-x" "$0" "$@" && [ ] if false
+#!ruby
 # This needs ruby 1.9 and subversion.
 # run this in a repository to commit.