Backport:

Introduce a per request version of the remote IP address, which can be
optionally modified by a module when the effective IP of the client
is not the same as the real IP of the client (such as a load balancer).
Introduce a per connection "peer_ip" and a per request "client_ip" to
distinguish between the raw IP address of the connection and the effective
IP address of the request.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1208378 13f79535-47bb-0310-9956-ffa450edef68