### Environment

* Dubbo version: 2.7.5
* Operating System version: win10 or centos7
* Java version: 1.8.0
* Zookeeper version: 3.5.6

### Steps to reproduce this issue
My previous dubbo service version was 2.7.3. Today, I upgraded to 2.7.5. I found that the metadata can't be displayed all the time. The dubbo service registry in zookeeper, but zookeeper not /dubbo/metadata node path view.  If I switch back to 2.7.3 and 2.7.4.1, it can be displayed. Are there any bugs? I need help~~

xml-config:
`<dubbo:metadata-report address="zookeeper://192.168.11.100:2181?backup=192.168.11.105:2181" />`
```

public String getRepository() {
        return repository;
    }
    public void setRepository(String repository) {
        this.repository = repository;
    }
    @Override
    public void refresh() {
        super.refresh();
        appendEnvironmentProperties();
    }
    private void appendEnvironmentProperties() {
        if (parameters == null) {
            parameters = new HashMap<>();
        }
        Set<InfraAdapter> adapters = ExtensionLoader.getExtensionLoader(InfraAdapter.class).getSupportedExtensionInstances();
        if (CollectionUtils.isNotEmpty(adapters)) {
            Map<String, String> inputParameters = new HashMap<>();
            inputParameters.put(APPLICATION_KEY, getName());
            inputParameters.put(HOST_KEY, getHostname());
            for (InfraAdapter adapter : adapters) {
                Map<String, String> extraParameters = adapter.getExtraAttributes(inputParameters);
                if (CollectionUtils.isNotEmptyMap(extraParameters)) {
                    parameters.putAll(extraParameters);
                }
            }
        }
    }
}