### 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

for (URL registryURL : registryURLs) {
                        //
                        if (LOCAL_PROTOCOL.equalsIgnoreCase(url.getProtocol())) {
                            continue;
                        }
                        url = url.addParameterIfAbsent(DYNAMIC_KEY, registryURL.getParameter(DYNAMIC_KEY));
                        URL monitorUrl = loadMonitor(registryURL);
                        if (monitorUrl != null) {
                            url = url.addParameterAndEncoded(MONITOR_KEY, monitorUrl.toFullString());
                        }
                        if (logger.isInfoEnabled()) {
                            logger.info("Register dubbo service " + interfaceClass.getName() + " url " + url + " to registry " + registryURL);
                        }
                        // 
                        String proxy = url.getParameter(PROXY_KEY);
                        if (StringUtils.isNotEmpty(proxy)) {
                            registryURL = registryURL.addParameter(PROXY_KEY, proxy);
                        }
                        Invoker<?> invoker = PROXY_FACTORY.getInvoker(ref, (Class) interfaceClass, registryURL.addParameterAndEncoded(EXPORT_KEY, url.toFullString()));
                        DelegateProviderMetaDataInvoker wrapperInvoker = new DelegateProviderMetaDataInvoker(invoker, this);
                        Exporter<?> exporter = protocol.export(wrapperInvoker);
                        exporters.add(exporter);
                    }
                } else {
                    Invoker<?> invoker = PROXY_FACTORY.getInvoker(ref, (Class) interfaceClass, url);
                    DelegateProviderMetaDataInvoker wrapperInvoker = new DelegateProviderMetaDataInvoker(invoker, this);
                    Exporter<?> exporter = protocol.export(wrapperInvoker);
                    exporters.add(exporter);
                }
                /**