Add support for X-Forwarded-For LWS

I know you've added this for the next release, but here is a fix
for LWS. But just incase there are any more 2.0.x releases.

It does leave the incoming port as 0 but as this is pretty meaningless
for a proxied connection I think it's probably ok.

Signed-off-by: Ben Hardill <hardillb@gmail.com>