Change the default depth and length of directories for mod_disk_cache to a...

Change the default depth and length of directories for mod_disk_cache to a depth of 2, and a length of 2.
Suggested By: noirin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@491364 13f79535-47bb-0310-9956-ffa450edef68