digipeater: remove empty packet from current connection after burst

impl/src/layer2/digipeater.c

@@ -289,6 +289,10 @@ size_t digipeater_encode_next_packet(digipeater_ctx_t *ctx, uint8_t *buf, size_t
 				if(connection_can_transmit(conn)) {
 					packet_size = connection_encode_next_packet(conn, buf, buf_len, end_burst);
 
+					if(*end_burst) {
+						connection_tx_clean_empty_packet(conn);
+					}
+
 					ctx->state = DIGIPEATER_STATE_CONN;
 				}
 			}

impl/test/layer2_over_udp/l2udptest_digipeater.c

@@ -248,9 +248,6 @@ int main(int argc, char **argv)
 				}
 			}
 
-			// FIXME: where to put this in the digipeater?
-			//connection_tx_clean_empty_packet(&l2conn);
-
 			LOG(LVL_DEBUG, "Burst finished: %zd packets sent.", burst_len);
 		}