'svn log' on non-root paths has a performance regression in 1.8 when run against
old servers that don't support get-location-segments. The libsvn_client
implementation of log calls svn_ra_get_location_segments which gets the full log
when the server doesn't support get-location-segments. The result is that the
client gets the whole repository log before requesting a second log for the
subset of interest.