DEVEL15-windows-local-directory-updates-20070802

DEVEL15-windows-local-directory-updates-20070802

The windows cache manager has suffered from poor performance as a result
of Create, Rename, and Delete operations because they invalidate the
contents of the directory pages in the cache thereby forcing them to be
reloaded from the file server.   As the directory size increases, the clock
time necessary to perform the reload increases.

This delta adds support for parsing and updating the AFS3 directory buffers
to cm_dir.c.  It then uses that functionality to perform local updates to
the directory buffers whenever the following conditions are met:

 1. the data version on the directory as a result of the change
    was incremented by one.

 2. all of the directory buffers required for the update are in
    the cache.

If these conditions are not met, the directory is reloaded from the file
server.

(cherry picked from commit c4047f6cb52927890329b09669b1a2686ace6059)