Improve delete notifications from the repository diff and make sure the
callbacks are properly called for directory deletes if walk_deleted is off.

* subversion/libsvn_client/repos_diff.c
  (send_delete_notify): New function, extracted from close_directory.
  (diff_deleted_dir): If walk_deleted_repos_dirs still report the delete
    of the directory itself. Send outstanding deletes before deleting the
    directory itself.
  (close_directory): Use send_delete_notify.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1437793 13f79535-47bb-0310-9956-ffa450edef68