Restore previous behavior of GetSha1ForSvnRev, so unit tests pass.

tests/scm_unittest.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Unit tests for scm.py."""
 
 import logging
 import os
 import sys
@@ skipping 61 matching lines @@
 
 class GitWrapperTestCase(BaseSCMTestCase):
   def testMembersChanged(self):
     members = [
         'AssertVersion',
         'Capture',
         'CaptureStatus',
         'current_version',
         'FetchUpstreamTuple',
         'GenerateDiff',
+        'GetBlessedSha1ForSvnRev',
         'GetBranch',
         'GetBranchRef',
         'GetCheckoutRoot',
         'GetDifferentFiles',
         'GetEmail',
         'GetGitSvnHeadRev',
         'GetPatchName',
         'GetSha1ForSvnRev',
         'GetSVNBranch',
         'GetUpstreamBranch',
@@ skipping 374 matching lines @@
     # Asserting the tree is not sufficient, svn status must come out clear too.
     self.assertEquals('', self._capture(['status']))
 
 
 if __name__ == '__main__':
   if '-v' in sys.argv:
     logging.basicConfig(level=logging.DEBUG)
   unittest.main()
 
 # vim: ts=2:sw=2:tw=80:et: