Consider an empty dns response the same as a no domain error.
Consider an empty dns response the same as a no domain error.

Some domains return an empty response rather than an NXDOMAIN error.
This helps us treat them the same, since we were handling NXDOMAIN
errors a bit more gracefully.

apinf/api-umbrella,apinf/api-umbrella,NREL/api-umbrella,NREL/api-umbrella-router,OdiloOrg/api-umbrella-router,NREL/api-umbrella,NREL/api-umbrella,NREL/api-umbrella-router,apinf/api-umbrella,OdiloOrg/api-umbrella-router,NREL/api-umbrella-router,apinf/api-umbrella,NREL/api-umbrella,OdiloOrg/api-umbrella-router,apinf/api-umbrella