Replace unusable/fringe absolute path example for AddDescription and list

some weird AddDescription semantics related to directories.

-This line, and those below, will be ignored--

M    mod_autoindex.xml


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1206680 13f79535-47bb-0310-9956-ffa450edef68