Endpoint.Namespace is not being set when it has no resolved endpoints

Create a service that has no resolved pods and therefore no Endpoints.endpoints, you get an entry in etcd that has an un-populated Endpoints.Namespace value.  

Note the object is created in the right part of the etcd hierarchy for the namespace, but it's just missing the Namespace value.

```
kubectl -n other create -f myservice.json
curl -u vagrant:vagrant -k https://10.245.1.2/api/v1beta1/endpoints?namespace=foo | python -mjson.tool
{
    "apiVersion": "v1beta1",
    "creationTimestamp": null,
    "items": [
        {
            "creationTimestamp": "2014-11-24T19:17:56Z",
            "id": "zk-mdi",
            "resourceVersion": 30,
            "selfLink": "/api/v1beta1/endpoints/zk-mdi",
            "uid": "9871ed6c-740e-11e4-b811-0800279696e1"
        }
    ],
    "kind": "EndpointsList",
    "resourceVersion": 30,
    "selfLink": "/api/v1beta1/endpoints"
}
```