Reduce ra_svn protocol parsing overhead.

* subversion/libsvn_ra_svn/marshal.c
  (vparse_tuple): test for the most frequent item types first


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1485499 13f79535-47bb-0310-9956-ffa450edef68
* CHANGES (1.6.23, 1.7.10): Tweak one entry.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1485501 13f79535-47bb-0310-9956-ffa450edef68