Previously, we did not require the 'service-name.*' host header value
when on a single http service was exposed. However, this allows a user
to get into a situation where, if they add another service to the
listener, suddenly the previous service's traffic might not be routed
correctly. Thus, we always require the Host header, even if there is
only 1 service.
Also, we add the make the default domain matching more restrictive by
matching "service-name.ingress.*" by default. This lines up better with
the namespace case and more accurately matches the Consul DNS value we
expect people to use in this case.