"minimal-responses no" is missing additional records from out-of-zone auth data

Reported on bind-users: When minimal-responses no is set, an authoritative query for an NS record which points to A records in another zone for which the server is also authoritative, the additional section is not being correctly populated.

This was introduced in change 4605 in 9.12.0, which deleted the call to query_getzonedb() when looking up additional data. That means we only search a single zone database, which is fine if minimal-responses is turned on but potentially incorrect if it isn't.