### Environment

* Dubbo version: 2.7.3
* Operating System version: CentOS7
* Java version: 1.8

### Steps to reproduce this issue

1. Set two protocal, with different "register" attribute

```xml
<dubbo:protocol name="dubbo" port="8751" register="true"  />
<dubbo:protocol name="hessian" port="8752" register="false" />
```

2. use the zookeeper registry center

```xml
<dubbo:registry address="..." file="./.dubbo_cache" />
```

3. start the server and view the provider in zkCli


### Expected Result
only the dubbo is registed

### Actual Result
the dubbo and hession protocol are registed

import static org.apache.dubbo.rpc.Constants.EXPORTER_LISTENER_KEY;
import static org.apache.dubbo.rpc.Constants.TOKEN_KEY;
/**
 * AbstractServiceConfig
 *
 * @export
 */
public abstract class AbstractServiceConfig extends AbstractInterfaceConfig {
    private static final long serialVersionUID = 1L;
    /**
     * The service version
     */
    protected String version;
    /**
     * The service group
     */
    protected String group;
    /**
     * whether the service is deprecated
     */
    protected Boolean deprecated = false;
    /**
     * The time delay register service (milliseconds)
     */
    protected Integer delay;
    /**
     * Whether to export the service
     */
    protected Boolean export;
    /**