Update mod_proxy_http proposal (missing ap_proxy_connection_reusable() in...

Update mod_proxy_http proposal (missing ap_proxy_connection_reusable() in 2.4.x), and remove Eric's vote.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1669102 13f79535-47bb-0310-9956-ffa450edef68