bittorrent-dht: set parser to unidirectional

This parser does not match up responses with requests so flag it as
unidirectional.

rust/src/bittorrent_dht/bittorrent_dht.rs

@@ -277,7 +277,7 @@ pub unsafe extern "C" fn rs_bittorrent_dht_udp_register_parser() {
         get_tx_data: rs_bittorrent_dht_get_tx_data,
         get_state_data: rs_bittorrent_dht_get_state_data,
         apply_tx_config: None,
-        flags: 0,
+        flags: APP_LAYER_PARSER_OPT_UNIDIR_TXS,
         truncate: None,
         get_frame_id_by_name: None,
         get_frame_name_by_id: None,