Fix error message.
Fix error message.

* tools/client-side/change-svn-wc-format.py
  (Entry.assert_valid_format): 'later versions' -> 'older versions'.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion