ObjectJob is always null when transferring domains

See #14 

When transferring domains, the result, the ObjectJob, contains only null objects:

```
class ObjectJob {
    job: null
    object: null
    niccomLogs: null
    authentication: null
    dcvAuth: null
}
```

When looking at the code, the error might also occur in the methods DomainClient.update, DomainClient.renew, DomainClient.updateStatus and DomainClient.restore.