knotc freeze on not exist domian checkzone

Hello!

I have installed knot 2.0.0 via http://deb.knot-dns.cz/knot/pool/main/k/knot/knot_2.0.0-1exp2bpo80%2b1_amd64.deb on debian 8.

If checked exists domain - it work good. But

knotc checkzone exapmle.org

as example freeze and "work" until you kill it.

Strace in attach. knotc_strace