gmqtt ignores wrongly set tls config about gmqtt

[bo-er]

The reason why I wasn't observing any issue is that I was starting mqtt server as what is shown in the example.
And to run a tls supported gmqtt server you should write your code like this:
Feel free to ask me for help!

	tlsCfg, err := buildTLSConfig(c.TLSOptions)
			if err != nil {
				logger.Fatalf("failed to build tls config:%v", err)
			}
			listener, err = tls.Listen("tcp", c.Address, tlsCfg)
			logger.Infof("mqtt will listen on port :%v in tls mode", c.Address)
			if err != nil {
				logger.Fatalf("failed to creates a TLS listener:%v", err)
			}

		} else {
			var err error
			listener, err = net.Listen("tcp", c.Address)
			if err != nil {
				panic(err)
			}
		}

func buildTLSConfig(cfg *config.TLSOptions) (*tls.Config, error) {
	c, err := tls.LoadX509KeyPair(cfg.Cert, cfg.Key)
	if err != nil {
		return nil, err
	}
	certPool := x509.NewCertPool()
	if cfg.CACert != "" {
		b, err := ioutil.ReadFile(cfg.CACert)
		if err != nil {
			return nil, err
		}
		certPool.AppendCertsFromPEM(b)
	}
	var cliAuthType tls.ClientAuthType
	if cfg.Verify {
		cliAuthType = tls.RequireAndVerifyClientCert
	}
	tlsCfg := &tls.Config{
		Certificates: []tls.Certificate{c},

		//servers clientCA to verify a client certificate
		ClientCAs: certPool,
		// ClientAuth determines the server's policy for
		// TLS Client Authentication.
		ClientAuth: cliAuthType,
	}
	return tlsCfg, nil
}