Minor tweaks to symmetric merge.
Minor tweaks to symmetric merge.

* subversion/libsvn_client/merge.c
  (svn_client__symmetric_merge_t): Tweak comment.
  (find_symmetric_merge): Add a minimal doc string.
  (svn_client__find_symmetric_merge): Remove unwanted comments.
  (do_symmetric_merge_locked): Remove unwanted comments. Add a
    TODO comment. Pass real instead of dummy depth, ignore_ancestry,
    force and record_only parameters.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1303041 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion