update mqttd main.c, fix debug with java bug for JSON with \0 bug

guowenxue

2019-08-03 2f6051f61e62ac477622f02708cb8eb13bc0ca51

 apue/2.Socket/ds18b20.c

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

    return 0;
}