Improve r28113, the fix for issue #3032 regarding merges from renamed branches.
Improve r28113, the fix for issue #3032 regarding merges from renamed
branches.

* subversion/libsvn_client/merge.c
  (do_directory_merge): Re-do the fix committed in r28113 in a much
    simpler, much more performant way.

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