Typo.

src/websockets.c

@@ -130,7 +130,7 @@ static int callback_mqtt(struct libwebsocket_context *context,
 		case LWS_CALLBACK_CLOSED:
 			mosq = u->mosq;
 			mqtt3_context_disconnect(db, mosq);
-			if(context->clean_session){
+			if(mosq->clean_session){
 				mqtt3_context_cleanup(db, mosq, true);
 			}
 			mosq->wsi = NULL;