remove {root-}delegation-only

complete the removal of the delegation-only and root-delegation-only
options, and the delegation-only zone type.

bin/tests/system/checkconf/deprecated.conf

@@ -23,8 +23,6 @@ options {
 	use-v6-udp-ports { range 1024 65535; };
 	avoid-v4-udp-ports { range 1 1023; };
 	avoid-v6-udp-ports { range 1 1023; };
-
-	root-delegation-only exclude { "them"; };
 };
 
 trusted-keys {
@@ -54,13 +52,3 @@ zone example.com {
 	file "maxttl-bad.db";
 	max-zone-ttl 120;
 };
-
-zone "." {
-	type hint;
-	file "shared.example.db";
-	delegation-only yes;
-};
-
-zone com {
-	type delegation-only;
-};