Switch libsvn_ra_serf's http error parser to the transition based xml parser
and at the same time stop ignoring most multi response status reports, such
as used by property and revision property changes.

* subversion/libsvn_ra_serf/multistatus.c
  New file.

* subversion/libsvn_ra_serf/ra_serf.h
  (svn_ra_serf__server_error_t): Replace some variables by a list of internal
    per path/property items that is later parsed into an error.
  (svn_ra_serf__setup_error_parsing,
   svn_ra_serf__handle_server_error): New function.

* subversion/libsvn_ra_serf/util.c
  (start_error,
   end_error,
   cdata_error,
   begin_error_parsing): Remove functions.

  (svn_ra_serf__expect_empty_body): Update caller.
  (parse_dav_status): Move to multistatus.c
  (start_207,
   end_207,
   cdata_207): Remove functions.
  (svn_ra_serf__handle_multistatus_only): Move to multistatus.c
  (handle_response): Update caller. Extract some code to
    svn_ra_serf__handle_server_error in multistatus.c
  (svn_ra_serf__error_on_status): Provide handling for a few more status values.
  (expat_response_handler): Make sure we don't convert an existing error parser.

* subversion/tests/cmdline/prop_tests.py
  (invalid_propvalues): Remove XFail marker. We just see the error after this
    patch (and the requested detailed message after r1553441).


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1553443 13f79535-47bb-0310-9956-ffa450edef68