Finish issue #4179 by eliminating no-op HEAD requests from ra_serf's checkout/update logic.
Finish issue #4179 by eliminating no-op HEAD requests from ra_serf's
checkout/update logic.

* subversion/libsvn_ra_serf/update.c
  (handle_local_contents): Was local_fetch().  Callers updated.  Also,
    decrement the directory reference count.
  (handle_local_fetch): Remove as unused.
  (fetch_file): Avoid HEAD requests where locally cached file contents
    are available.  Instead, either immediately handle the contents,
    or squirrel away some state so we remember to do so...
  (finish_report): ...here.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1348131 13f79535-47bb-0310-9956-ffa450edef68

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