Fix "Warning: Connection leak" log messages.

A follow along fix for TS-3901.

It looks like there is another drift between the cached server IP value used to insert into the session pool (HttpServerSession::server_ip) and the cached server IP value used to look up from the session pool (NetVConnection::remote_addr).

I'm guessing that the HttpServerSession value was added to avoid calling vc->get_remote_addr() multiple times. But the vc also caches the remote addr, so calls to vc->get_remote_addr should be pretty cheap.

Added a debug print to better understand the difference between vc->get_remote_addr() and server_session->server_ip. In this case, the differences are in the ports.

DEBUG: (http_ss) remote_ip=xx.xx.xx.xx:3128, server_ip=xx.xx.xx.xx:80

Specifically, vc->get_remote_addr() is the first value and reflects the "real" port used to connection to the server. The server_ip port is the pre-remap port.

We ended up using remote_ip for both server session insert and lookup and things have been running solidly for us.