Following up on r1445904, apply some diff processor correctness to the
repos-wc diff editor.

* subversion/libsvn_wc/diff_editor.c
  (handle_local_only): When skipping children, skip them here too.
  (report_base_only_dir): Add missing parenthesis.
  (open_root): When the root is the target, handle it like a target, and
    if not don't report a final not-changed.
  (close_directory): Handle skipping children.

  (add_file,
   open_file): Avoid doing unneeded work.

  (apply_textdelta): Provide the explicit null handler when ignoring the
    delta to tell smart ra layers (such as ra_serf) to really avoid
    transferring the file if possible.

  (close_file): Don't expect a valid result file when skipping. Don't
    produce a change when skipping.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1446068 13f79535-47bb-0310-9956-ffa450edef68