Fix a problem in the ra_serf replay implementation which caused 404
responses to the REPORT requests to go unnoticed.

* subversion/libsvn_ra_serf/replay.c
  (replay_context_t): Add 'report_hander' member.
  (svn_ra_serf__replay, svn_ra_serf__replay_range): Initialize new
    'report_handler' replay context baton member, and use it to check
    for errors (based on status code) in the completed REPORT
    response(s).


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1432376 13f79535-47bb-0310-9956-ffa450edef68