Update sockets.c

1、更正lwip_accept()中调用netconn_peer()失败时，netconn_delete()会被调用两次，从而导致进入rt_assert_handler()错误。
原因：(https://savannah.nongnu.org/bugs/?55536) bug #55536: lwIP 2.1.2: netconn_delete() called twice from lwip_accept()

components/net/lwip-2.1.2/src/api/sockets.c

@@ -710,7 +710,7 @@ lwip_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
     err = netconn_peer(newconn, &naddr, &port);
     if (err != ERR_OK) {
       LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): netconn_peer failed, err=%d\n", s, err));
-      netconn_delete(newconn);
+      //netconn_delete(newconn);
       free_socket(nsock, 1);
       sock_set_errno(sock, err_to_errno(err));
       done_socket(sock);