Leak fix

src/libknot/zone/zone-contents.c

@@ -144,12 +144,14 @@ static int knot_zone_contents_nsec3_name(const knot_zone_contents_t *zone,
 		return KNOT_ENSEC3PAR;
 	}
 
-	const char *apex_name = knot_dname_to_str(knot_node_owner(
-					knot_zone_contents_apex(zone)));
+	char *apex_name = knot_dname_to_str(knot_node_owner(
+	                                        knot_zone_contents_apex(zone)));
 	assert(apex_name);
 
 	*nsec3_name = create_nsec3_owner(name, nsec3_params, apex_name,
 	                                 strlen(apex_name));
+	free(apex_name);
+
 	if (nsec3_name == NULL) {
 		return KNOT_ERROR;
 	}