dns_message_reply(): copy the question section of notify messages.

lib/dns/include/dns/message.h

@@ -771,11 +771,11 @@ dns_message_reply(dns_message_t *msg, isc_boolean_t want_question_section);
  * Ensures:
  *
  *	The message will have a rendering intent.  If 'want_question_section'
- *	is true, the message opcode is query, and the question section is
- *	present and properly formatted, then the question section will be
- *	included in the reply.  All other sections will be cleared.  The QR
- *	flag will be set, the RD flag will be preserved, and all other flags
- *	will be cleared.
+ *	is true, the message opcode is query or notify, and the question
+ *	section is present and properly formatted, then the question section
+ *	will be included in the reply.  All other sections will be cleared.
+ *	The QR flag will be set, the RD flag will be preserved, and all other
+ *	flags will be cleared.
  *
  * Returns:
  *

lib/dns/message.c

@@ -1918,7 +1918,8 @@ dns_message_reply(dns_message_t *msg, isc_boolean_t want_question_section) {
 
 	if (!msg->header_ok)
 		return (DNS_R_FORMERR);
-	if (msg->opcode != dns_opcode_query)
+	if (msg->opcode != dns_opcode_query &&
+	    msg->opcode != dns_opcode_notify)
 		want_question_section = ISC_FALSE;
 	if (want_question_section) {
 		if (!msg->question_ok)