### 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

/**
     * Development environment key.
     */
    String DEVELOPMENT_ENVIRONMENT = "develop";
    /**
     * Production environment key.
     */
    String PRODUCTION_ENVIRONMENT = "product";
    String CONFIG_CONFIGFILE_KEY = "config.config-file";
    String CONFIG_ENABLE_KEY = "config.highest-priority";
    String CONFIG_TIMEOUT_KEY = "config.timeout";
    String CONFIG_APPNAME_KEY = "config.app-name";
    String MULTICAST = "multicast";
    String DUBBO_IP_TO_REGISTRY = "DUBBO_IP_TO_REGISTRY";
    String DUBBO_PORT_TO_REGISTRY = "DUBBO_PORT_TO_REGISTRY";
    String DUBBO_PORT_TO_BIND = "DUBBO_PORT_TO_BIND";
    String SCOPE_NONE = "none";
    String ON_INVOKE_METHOD_KEY = "oninvoke.method";
    String ON_RETURN_METHOD_KEY = "onreturn.method";
    String ON_THROW_METHOD_KEY = "onthrow.method";
    String ON_INVOKE_INSTANCE_KEY = "oninvoke.instance";
    String ON_RETURN_INSTANCE_KEY = "onreturn.instance";
    String ON_THROW_INSTANCE_KEY = "onthrow.instance";
    
    String SHUTDOWN_TIMEOUT_KEY = "shutdown.timeout";
    String PROTOCOLS_SUFFIX = "dubbo.protocols.";
    String REGISTRIES_SUFFIX = "dubbo.registries.";
    String ZOOKEEPER_PROTOCOL = "zookeeper";
}