BUG/MAJOR: dns: first DNS response packet not matching queried hostname may lead...

BUG/MAJOR: dns: first DNS response packet not matching queried hostname may lead to a loop

The status DNS_UPD_NAME_ERROR returned by dns_get_ip_from_response and
which means the queried name can't be found in the response was
improperly processed (fell into the default case).
This lead to a loop where HAProxy simply resend a new query as soon as
it got a response for this status and in the only case where such type
of response is the very first one received by the process.

This should be backported into 1.6 branch