Default off (for now), as some older software that gives nxdomain for ENT
would be incompatible. But that would only happen in the reverse tree, and
such software (nonDNSSEC) may go out of style, so in the future a default yes
could be possible.
git-svn-id: file:///svn/unbound/trunk@2347 be551aaa-1e26-0410-a405-d3ace91eadb9