handle_multi: pass along the original path info and query string if

we redirect due to negotiation

pointed out by: Bill Rowe

also, clarify what some code in handle_map_file is doing


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93061 13f79535-47bb-0310-9956-ffa450edef68