sms: domain is not allocated in pkg by the module

- skip freeing in mod destroy

modules/sms/sms.c

@@ -668,9 +668,6 @@ static int sms_init(void)
 
 static int sms_exit(void)
 {
-	if ((!domain_str) && (domain.s))
-		pkg_free(domain.s);
-
 	if (queued_msgs)
 		shm_free(queued_msgs);