Fixed malformed response from bad ARCOUNT

[artur99]

_authority and _additional are never filled with data but at response, the corresponding counters are not 0 but contain the counters from the request which will produce a malformed response.

For example, running dig @127.0.0.1 facebook.com A would show a warning like this: ;; Warning: Message parser reports malformed message packet. Caused by the fact that at request the ARCOUNT is 1, but at response, there's no Additional Response entries, but the counter is set to 1.