Nsec dname cmp zero
This "solves" the situation when records in zone are wrongly ordered because of knot_dname_lf with connection to \000.
The user is warned when creating NSEC tree, when owner with \000 is present.
NSEC tree creation/update fails, if this directly affects zone ordering.
This does not solve many situations when there is collision of names after knot_dname_lf applied!