The dboption DNS_DBFIND_STALEONLY caused confusion because it implies we are looking for stale data **only** and ignore any active RRsets in the cache. Rename it to DNS_DBFIND_STALETIMEOUT as it is more clear the option is related to a lookup due to "stale-answer-client-timeout". Rename other usages of "staleonly", instead use "lookup due to...". Also rename related function and variable names.