Define two macros that should make using our most common type of apr_hash_t *
instances much easier.

* subversion/include/svn_hash.h
  (svn_hash_gets,
   svn_hash_sets): New macros.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1443387 13f79535-47bb-0310-9956-ffa450edef68