Fix proxy so that it is possible to access ftp: URLs via a proxy

chain.
PR:
Obtained from:
Submitted by:	Peter Van Biesen <peter.vanbiesen@vlafo.be>
Reviewed by:	Graham Leggett <minfrin@apache.org>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@96320 13f79535-47bb-0310-9956-ffa450edef68