4770. [bug] Cache additional data from priming queries as glue.
Previously they were ignored as unsigned
non-answer data from a secure zone, and never
actually got added to the cache, causing hints
to be used frequently for root-server
addresses, which triggered re-priming. [RT #45241]
(cherry picked from commit 5de02a075b)
(cherry picked from commit 6216df5ccd)