can not recurse further and it finds the delegation in a state
where it would otherwise have rejected it outhand if so received
from a cache lookup, then it can try to ask higherup (with loop
protection).
- Fix comments in iter_utils:dp_is_useless.
git-svn-id: https://unbound.nlnetlabs.nl/svn/trunk@2114 be551aaa-1e26-0410-a405-d3ace91eadb9
