cleanup: allow building DS directly from CDNSKEY
Relax an assertion in lib/dns/ds.c so that dnssec-cds does not have to work around it. This will also be useful for dnssec-dsfromkey.
(cherry picked from commit 2e173bbd)
Relax an assertion in lib/dns/ds.c so that dnssec-cds does not have to work around it. This will also be useful for dnssec-dsfromkey.
(cherry picked from commit 2e173bbd)