Add htcacheclean to function as cleanup utility (daemonizable) for

mod_disk_cache.

(Justin did a whole bunch of style tweaks, and some minor functionality tweaks
to get it to function on Solaris.)

Submitted by:	Andreas Steinmetz
Reviewed by:	Justin Erenkrantz


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@105698 13f79535-47bb-0310-9956-ffa450edef68