session_get_tcp_segment() and session_free_tcp_segment() support asynchronous calls

src/session/session_manager.cpp

@@ -305,6 +305,7 @@ static void tcp_update(struct session_manager *mgr, struct session *sess, enum f
 
                half->in_order.data = tcp_layer->pld_ptr;
                half->in_order.len = len;
+               half->in_order_ref = 0;
           }
           return;
      }
@@ -345,6 +346,7 @@ static void tcp_update(struct session_manager *mgr, struct session *sess, enum f
 
                half->in_order.data = tcp_layer->pld_ptr;
                half->in_order.len = len;
+               half->in_order_ref = 0;
                tcp_reassembly_inc_recv_next(half->assembler, len);
           }
           // retransmission