Minor ra_svn marshaller tuning.

* subversion/libsvn_ra_svn/marshal.c
  (svn_ra_svn__parse_proplist): use our faster hash function


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1486015 13f79535-47bb-0310-9956-ffa450edef68