Modified cache garbage control to first check if it

actually should run, based on the time of last run,
and to try to get a lock; prior to actually forking
and doing the real cleanup. This effectively avoids
a fork after each and every request; and limites
the spawning to just once every few hours.
PR:
Obtained from:
Submitted by:
Reviewed by:


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@83036 13f79535-47bb-0310-9956-ffa450edef68