Fix another client Ev2 shim callback to provide a non-NULL hash.
Fix another client Ev2 shim callback to provide a non-NULL hash.

* subversion/libsvn_client/util.c
  (fetch_props_func): If the WC returns a NULL prophash, we want to return
    an empty one.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion