First cut at kernel oplocks. This should have no effect unless runnin

First cut at kernel oplocks. This should have no effect unless runnin
on a machine that supports them in autoconf.

Move various functions out of lib/util.c into smbd/process.c
and smbd/oplock.c where they belong.

Jeremy.
(This used to be commit c3c5e13f85c97939746070132dad941e79c546fb)