resource_record can't update NS records

[inkblot]

The nsupdate provider for the resource_record resource type can't update an NS record*. The provider attempts to remove all records for the name and then add the correct ones when there is any discrepancy in the resource properties. This does not work for NS records because the nameserver rejects the removal of all of a zone's NS records.

• Except in the special case of a glue record