Before binding an RRset, check the time and see if this record is
stale (or perhaps even ancient). Marking a header stale or ancient
happens only when looking up an RRset in cache, but binding an RRset
can also happen on other occasions (for example when dumping the
database).
Check the time and compare it to the header. If according to the
time the entry is stale, but not ancient, set the STALE attribute.
If according to the time is ancient, set the ANCIENT attribute.
We could mark the header stale or ancient here, but that requires
locking, so that's why we only compare the current time against
the rdh_ttl.
Adjust the test to check the dump-db before querying for data. In the
dumped file the entry should be marked as stale, despite no cache
lookup happened since the initial query.
debee6157b