- [x] I have searched the [issues](https://github.com/apache/incubator-dubbo/issues) of this repository and believe that this is not a duplicate.
- [x] I have checked the [FAQ](https://github.com/apache/incubator-dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: xxx
* Operating System version: xxx
* Java version: xxx

### Steps to reproduce this issue

`org.apache.dubbo.remoting.etcd.jetcd.JEtcdClientWrapper#doClose`:

```
if (globalLeaseId > 0) {
        revokeLease(this.globalLeaseId);
}
```

should be change to :

```
if (globalLeaseId != 0) {
        revokeLease(this.globalLeaseId);
}
```


Pls. provide [GitHub address] to reproduce this issue.

### Expected Result

What do you expected from the above steps？

### Actual Result

What actually happens?

If there is an exception, please attach the exception trace:

```
Just put your stack trace here!
```

retryFuture.cancel(true);
            retryExecutor.shutdownNow();
        } catch (Throwable t) {
            logger.warn(t.getMessage(), t);
        }
        if (getClient() != null) getClient().close();
    }
    /**
     * try get client's shared channel, becase all fields is private on jetcd,
     * we must using it by reflect, in the future, jetcd may provider better tools.
     *
     * @param client get channel from current client
     * @return current connection channel
     */
    private ManagedChannel newChannel(Client client) {
        try {
            Field connectionField = client.getClass().getDeclaredField("connectionManager");
            if (!connectionField.isAccessible()) {
                connectionField.setAccessible(true);
            }
            Object connection = connectionField.get(client);
            Method channel = connection.getClass().getDeclaredMethod("getChannel");
            if (!channel.isAccessible()) {
                channel.setAccessible(true);
            }
            return (ManagedChannel) channel.invoke(connection);
        } catch (Exception e) {
            throw new RuntimeException("Failed to obtain connection channel from " + url.getBackupAddress(), e);
        }
    }