[1836] added a lettuce test case for delegation from unsigned zone with DO bit.

this would identify the bug fixed in this branch.

tests/lettuce/features/queries.feature

@@ -79,3 +79,19 @@ Feature: Querying feature
         ns2.example.org.	3600	IN	A	192.0.2.4
         mail.example.org.	3600	IN	A	192.0.2.10
         """
+    Scenario: Delegation query for unsigned child zone
+        Given I have bind10 running with configuration example.org.inmem.config
+        A dnssec query for www.sub.example.org type AAAA should have rcode NOERROR
+        The last query response should have flags qr rd
+        The last query response should have edns_flags do
+        The last query response should have ancount 0
+        The last query response should have nscount 1
+        The last query response should have adcount 2
+        The authority section of the last query response should be
+        """
+        sub.example.org.	3600	IN	NS	ns.sub.example.org.
+        """
+        The additional section of the last query response should be
+        """
+        ns.sub.example.org.	3600	IN	A	192.0.2.101
+        """