Remove some unnecessary work from from our "ls" code.

* subversion/libsvn_client/list.c
  (get_dir_contents): don't attempt to match locks when there are none

* subversion/libsvn_ra_svn/client.c
  (ra_svn_get_dir): according to the protocol spec, we send the name
                    of the dirents (i.e. 1 segment) -- never a multi-
                    segment relpath.  There is nothing to canonicalize.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1533392 13f79535-47bb-0310-9956-ffa450edef68