Automatic merge from submit-queue

return warning on empty list result in kubectl get

**Release note**:
```release-note
NONE
```

The current default behavior of `kubectl get` is to return an empty
output when there are no resources to display. This patch improves
usability by returning a warning through stderr in the case of an empty
list.

##### Before
`$ kubectl get pods`
  - *empty output*

##### After
`$ kubectl get pods`
```
There are no resources to display.
```