Handle CNAME and DNAME in resume_min in a special way

When authoritative zone is loaded when query minimization query for the
same zone is already pending, it might receive unexpected result codes.

Normally DNS_R_CNAME would follow to query_cname after processing sent
events, but dns_view_findzonecut does not fill CNAME target into
event->foundevent. Usual lookup via query_lookup would always have that
filled.

Ideally we would restart the query with unmodified search name, if
unexpected change from recursing to local zone cut were detected. Until
dns_view_findzonecut is modified to export zone/cache source of the cut,
at least fail queries which went into unexpected state.

lib/dns/resolver.c

@@ -4284,8 +4284,14 @@ resume_qmin(void *arg) {
 	 * DNS_R_NXDOMAIN here means we have not loaded the root zone
 	 * mirror yet - but DNS_R_NXDOMAIN is not a valid return value
 	 * when doing recursion, we need to patch it.
+	 *
+	 * CNAME or DNAME means zone were added with that record
+	 * after the start of a recursion. It means we do not have
+	 * initialized correct hevent->foundname and have to fail.
 	 */
-	if (result == DNS_R_NXDOMAIN) {
+	if (result == DNS_R_NXDOMAIN || result == DNS_R_CNAME ||
+	    result == DNS_R_DNAME)
+	{
 		result = DNS_R_SERVFAIL;
 	}