Our outgoing (request) Via: header seems to always default to 127.0.0.1 as the IP identifier

This can cause serious problems, because if the other end is also an ATS server, also defaulting to thinking it's on 127.0.0.1, will treat this as a loop, and send a 400 response.

We ought to try to send something more intelligent as the hex-IP in the request Via: header. This is particularly problematic when ATS is used as a forward (or intercepting) proxy, and have outgoing Via: headers enabled.