Added ap_proxy_connection_create function that makes

conn_rec for opened connection. It is used bt http(s) and ftp for
bounding the backend connection to client connection with the same id's.

Submitted by: mturk


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@104597 13f79535-47bb-0310-9956-ffa450edef68