More cleanup in the libsvn_ra_serf commit handling. Consistently use commit_ctx
as the baton name and don't use proppatch specific error codes for other DAV
operations.

* subversion/include/svn_error_codes.h
  (SVN_ERR_RA_DAV_PRECONDITION_FAILED): New error code.

* subversion/libsvn_client/commit.c
  (fixup_commit_error): Handle more error codes as implying out of date.

* subversion/libsvn_ra_serf/commit.c
  (proppatch_context_t,
   delete_context_t,
   dir_context_t,
   file_context_t): Rename commit context to commit_ctx.
  (retry_checkout_node): Add error tracing.
  (checkout_dir): Add error tracing. Leave wrapping to libsvn_client.
  (checkout_file): Add error tracing. Leave wrapping to libsvn_client.
  (setup_proppatch_headers): Update caller. Skip lock header when not in a
    commit.
  (proppatch_body_baton_t): Remove unneeded baton.
  (create_proppatch_body): Use proppatch_context_t as baton. Allocate body temp
    vars in scratch_pool.
  (proppatch_resource): Remove commit context requirement.
  (setup_put_headers,
   setup_add_dir_common_headers,
   setup_copy_dir_headers,
   setup_delete_headers): Update caller.
  (open_root): Use function internal scratch pool for requests.
  (delete_entry,
   add_directory,
   open_directory,
   close_directory,
   add_file,
   open_file,
   close_file): Update caller.
  (svn_ra_serf__change_rev_prop): Update caller. Stop setting up commit
    context. Replace specific error code.

* subversion/libsvn_ra_serf/multistatus.c
  (multistatus_closed): Use actual request error code instead of hardcoded 500.
  (multistatus_done): Make reported status leading for a proper error chain.
    Produce a bit more information we get from the multistatus reports.

* subversion/libsvn_ra_serf/ra_serf.h
  (svn_ra_serf__server_error_t): Store sline. Drop method as we already know
    that where needed.

* subversion/libsvn_ra_serf/util.c
  (svn_ra_serf__error_on_status): Improve handling of http status 409 and 412.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1553668 13f79535-47bb-0310-9956-ffa450edef68