net/tcp: listen for read events after async connect

After an async connect succeeds, the fd should also be added in reactor
for read events, otherwise these will be lost.

Many thanks go to Pete Kelly for reporting and testing!

(cherry picked from commit ca643de)

net/net_tcp.c

@@ -1147,6 +1147,11 @@ inline static int handle_tcpconn_ev(struct tcp_connection* tcpconn, int fd_i,
 			tcpconn->state = S_CONN_OK;
 			LM_DBG("Successfully completed previous async connect\n");
 
+			/* now that we completed the async connection, we also need to
+			 * listen for READ events, otherwise these will get lost */
+			if (tcpconn->flags & F_CONN_REMOVED_READ)
+				reactor_add_reader( tcpconn->s, F_TCPCONN, RCT_PRIO_NET, tcpconn);
+
 			goto async_write;
 		} else {
 			/* we're coming from an async write -