## 问题描述
使用如下方式配置RegistryConfig bean时

```java
    @Bean
    public RegistryConfig registryConfig() {
        RegistryConfig registryConfig = new RegistryConfig();
        registryConfig.setProtocol("zookeeper");
        registryConfig.setAddress("localhost");
        registryConfig.setPort(2181);
        return registryConfig;
    }
```

提示无法与zookeeper建立连接，调试代码发现，zookeeper链接为

`zookeeper://localhost:9090/ConfigCenterConfig?check=true&config-file=dubbo.properties&group=dubbo&highest-priority=false&namespace=dubbo&timeout=3000`

使用了9090端口，未使用2181端口，registryConfig.setPort()不生效。

对比测试，使用registryConfig.setAddress("localhost:2181")方式可以生效。


private List<ServiceDiscovery> getServiceDiscoveries() {
        return AbstractRegistryFactory.getRegistries()
                .stream()
                .filter(registry -> registry instanceof ServiceDiscoveryRegistry)
                .map(registry -> (ServiceDiscoveryRegistry) registry)
                .map(ServiceDiscoveryRegistry::getServiceDiscovery)
                .collect(Collectors.toList());
    }
    /**
     * Start the bootstrap
     */
    public DubboBootstrap start() {
        if (started.compareAndSet(false, true)) {
            initialize();
            if (logger.isInfoEnabled()) {
                logger.info(NAME + " is starting...");
            }
            
            exportServices();
            
            if (!isOnlyRegisterProvider() || hasExportedServices()) {
                
                exportMetadataService();
                
                registerServiceInstance();
            }
            referServices();
            if (logger.isInfoEnabled()) {
                logger.info(NAME + " has started.");
            }