DNAME not applied more than once to resolve the query

Hi,

I rechecked the DNAME behavior after (#703 (closed)) and found the following behavior different from BIND, PowerDNS.

campus.edu.	500 SOA	ns1.campus.edu. root.campus.edu. 3 86400 7200 604800 300
campus.edu.	500 NS	ns1.outside.edu.
campus.edu.	500 DNAME	edu.

For the query <campus.campus.campus.edu, NS>, the response returned by BIND and PowerDNS was:

        ";ANSWER",
        "campus.edu. 500 IN DNAME edu.",
        "campus.campus.campus.edu. 500 IN CNAME campus.campus.edu.",
        "campus.campus.edu. 500 IN CNAME campus.edu.",
        "campus.edu. 500 IN NS ns1.outside.edu.",
        ";AUTHORITY",
        ";ADDITIONAL"

whereas the response from Knot (NSD too) was:

        ";ANSWER",
        "campus.edu. 500 IN DNAME edu.",
        "campus.campus.campus.edu. 500 IN CNAME campus.campus.edu.",
        ";AUTHORITY",
        ";ADDITIONAL"

Since the DNAME is not applied more than once, it results in the NS record not being returned.

(Thanks for your quick responses to the bug reports :))