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

guowenxue

2019-08-03 2f6051f61e62ac477622f02708cb8eb13bc0ca51

 mqttd/main.c

@@ -295,7 +295,7 @@
        else 
            snprintf(msg, sizeof(msg), "{ \"id\":%s, \"temp\":\"%.2f\", \"RH\":\"%.2f\" }", ctx->id, temp, rh);

        rv = mosquitto_publish(mosq, NULL, ctx->pubTopic, strlen(msg)+1, msg, ctx->pubQos, retain);
        rv = mosquitto_publish(mosq, NULL, ctx->pubTopic, strlen(msg), msg, ctx->pubQos, retain);
        if( rv )
        {
            log_err("Publisher broadcast message '%s' failure: %d\n", msg, rv);