fixed bug: close sock when connect fail.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2287 bbd45198-f89e-11dd-88c7-29a3b14d5316

examples/network/tcpclient.c

@@ -44,7 +44,8 @@ void tcpclient(const char* url, int port)
     if (connect(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1)
     {
         /* 连接失败 */
-       rt_kprintf("Connect error\n");
+        rt_kprintf("Connect fail!\n");
+        lwip_close(sock);
 
         /*释放接收缓冲 */
         rt_free(recv_data);