Fix resolving svn revisions in release scripts.

tools/push-to-trunk/git_recipes.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 277 matching lines @@
     self.Git("svn rebase", **kwargs)
 
   # TODO(machenbach): Unused? Remove.
   @Strip
   def GitSVNLog(self, **kwargs):
     return self.Git("svn log -1 --oneline", **kwargs)
 
   @Strip
   def GitSVNFindGitHash(self, revision, branch="", **kwargs):
     assert revision
-    return self.Git(
-        MakeArgs(["svn find-rev", "r%s" % revision, branch]), **kwargs)
+    args = MakeArgs(["svn find-rev", "r%s" % revision, branch])
+
+    # Pick the last line if multiple lines are available. The first lines might
+    # print information about rebuilding the svn-git mapping.
+    return self.Git(args, **kwargs).splitlines()[-1]
 
   @Strip
   def GitSVNFindSVNRev(self, git_hash, branch="", **kwargs):
     return self.Git(MakeArgs(["svn find-rev", git_hash, branch]), **kwargs)
 
   def GitSVNDCommit(self, **kwargs):
     return self.Git("svn dcommit 2>&1", retry_on=lambda x: x is None, **kwargs)
 
   def GitSVNTag(self, version, **kwargs):
     self.Git(("svn tag %s -m \"Tagging version %s\"" % (version, version)),
              retry_on=lambda x: x is None,
              **kwargs)