- pull out the code that checks whether a key was signed by a trust
anchor into a separate function, anchor_signed().
- pull out the code that looks up a DS while validating a zone key
into a separate function, get_dsset().
- check in create_validator() whether the sigrdataset is bound, so that
we can always pass in &val->fsigrdataset during an insecurity proof;
this will allow a reduction of code duplication.
Evan Hunt
3a4334636b