lb/ForwardHttpRequest: set and unset FAILURE_FAILED for Zeroconf connect attempts
lb/ForwardHttpRequest: set and unset FAILURE_FAILED for Zeroconf connect attempts

The Zeroconf code doesn't use the tcp_balancer, which usually does
this for us.

CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy