add 2 new enviornment variables to deal with misbehaving backends

"proxy-nokeepalive" which removes the Connection: line completely
"force-proxy-request-1.0" which forces the request to be HTTP/1.0
this allows apache to reverse proxy misbehaving appservers


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@95456 13f79535-47bb-0310-9956-ffa450edef68