update mqttd main.c, add mosquitto publisher and subscriber

guowenxue

2019-06-25 02294c1c430ab80bd4543af28f867c5c2927e5c1

 apue/2.Socket/ds18b20.c

@@ -98,5 +98,7 @@
    /* convert string value to float value */
    *temp = atof(ptr)/1000;
   
    close(fd);

    return 0;
}