Use --internal-diff only for svn >= 1.7.

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 186 matching lines @@
   def testMembersChanged(self):
     self.mox.ReplayAll()
     members = [
         'AssertVersion',
         'Capture',
         'CaptureLocalInfo',
         'CaptureRemoteInfo',
         'CaptureRevision',
         'CaptureStatus',
         'current_version',
-        'DiffItem',
         'GenerateDiff',
         'GetCheckoutRoot',
         'GetEmail',
         'GetFileProperty',
         'IsMoved',
         'IsMovedInfo',
         'IsValidRevision',
         'ReadSimpleAuth',
         'Revert',
         'RunAndGetFileList',
@@ skipping 249 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: