Port the "squid %2f hack" from apache_1.3.24.

It is now possible to browse the root directory by using a url
like:   ftp://user@host/%2f/
Also, the last path component may contain wildcard characters
'*' and '?', and if they do, a directory listing is created instead
of a file retrieval. Example: ftp://user@host/httpd/server/*.c


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93108 13f79535-47bb-0310-9956-ffa450edef68