In the libsvn_client diff code: separate the diff driver generated state
from the diff writer/output state.

* subversion/libsvn_client/diff.c
  (make_repos_relpath): Replace ra_session argument with just the required
    value as a diff writer shouldn't need access to the network layer.

  (display_prop_diffs): Update forwarded arguments for make_repos_relpath.

  (diff_driver_info_t): New baton, extracted from diff_cmd_baton.
  (diff_cmd_baton): Rename to...
  (diff_writer_info_t): ... this. Extract some fields to an inner struct
    of type diff_driver_info_t.

  (diff_props_changed,
   diff_dir_props_changed,
   diff_content_changed,
   diff_file_changed,
   diff_file_added,
   diff_file_deleted): Update caller.

  (diff_wc_wc,
   diff_repos_repos,
   diff_repos_wc): Optionally fill an diff_driver_info_t instance
     instead of passing the whole baton.

  (do_diff,
   do_diff_summarize): Update caller.

  (set_up_diff_cmd_and_options): Rename to...
  (create_diff_writer_info): ... this.

  (svn_client_diff6,
   svn_client_diff_peg6): Update caller.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1569937 13f79535-47bb-0310-9956-ffa450edef68