The DNS_R_MUSTBESECURE lost its meaning with removal of dnssec-must-be-secure option, so replace the few remaining (and a bit confusing) use of this result code with DNS_R_NOVALIDSIG.
The DNS_R_MUSTBESECURE lost its meaning with removal of dnssec-must-be-secure option, so replace the few remaining (and a bit confusing) use of this result code with DNS_R_NOVALIDSIG.