Complete the transitioning from the merge code to the diff processor, by
making the handling of pending notifications part of all directory close
functions.

* subversion/libsvn_client/merge.c
  (handle_pending_notifications): New helper function. Based on the old
    merge_dir_closed code, which is now just a caller.

  (merge_dir_opened): Stay compatible with the old walk_children is false.

  (merge_dir_changed,
   merge_dir_added): Call handle_pending_notifications.

  (merge_dir_deleted,
   merge_dir_closed): Implement svn_diff_tree_processor_t callback.
                      Call handle_pending_notifications.

  (ignore_file_opened,
   ignore_file_changed,
   ignore_file_added,
   ignore_file_deleted,
   ignore_dir_opened,
   ignore_dir_props_changed,
   ignore_dir_added): Remove now unused stubs.

  (merge_callbacks): Remove unused variable.

  (do_merge): Complete initialization. Remove callback wrapper.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1440599 13f79535-47bb-0310-9956-ffa450edef68