Resolve performance issue when tracing locations against svn 1.0.x servers, by not requesting more log data than we really need.
Resolve performance issue when tracing locations against svn 1.0.x
servers, by not requesting more log data than we really need.

* subversion/libsvn_client/ra.c
  (log_receiver): Eliminate unnecessary special case.  Add a safety
   check to prevent an assertion failure if the server sends bogus
   log data.
  (slow_locations): Compute the oldest as well as the youngest
   revision, and only ask for the logs from youngest to oldest.  Use
   lrb.last_path to fill in any values not covered by the received log
   information.  Eliminate redundant code to start filling in the
   baton.  Avoid a network request in the common case when all three
   revisions are the same.

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