[telnet]reset cnt_conn when disable telnet session

modules/Telnet_Server/telnet_server.c

@@ -592,6 +592,7 @@ void vBasicSocketsCommandInterpreterTask( void *pvParameters )
 			if (!firstrun || sSettings.sTelnet.port != port) {
 				/* Stop server */
 				stop_server();
+				cnt_conn = 0;
 			}
 
 			if (sSettings.sTelnet.TelnetEnable) {