Merge r921347, r921583 from trunk:

mod_proxy_http: log backend port in various places

PR: 48812
Submitted by: igalic
Reviewed by: sf, pgollucci, trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@942878 13f79535-47bb-0310-9956-ffa450edef68