- Fix some golint errors for `pkg/kubectl`
- Fix a golint error for `pkg/kubectl/apps`
- Fix all golint errors for `pkg/kubectl/cmd`
- Fix some golint errors for `pkg/kubectl/generate/versioned`
- Fix a golint error for `pkg/kubectl/generate`
- Fix some golint errors for `pkg/kubectl/metricsutil`
- Fix all golint errors for `pkg/kubectl/util`
- Fix all golint errors for `pkg/kubectl/util/slice`
`parseFileSource()` and `parseLiteralSource()` are utility functions.
We have a package already for utility functions, `kubectl/util/`.
Move utility functions to `kubectl/util`, capitalize function names to
export from package.
Remove kubectl's dependence on pkg/api/helper, as part of
broader effort to isolate kubectl from the rest of k8s.
In this case, the code becomes private to kubectl; nobody else uses it.
**Which issue this PR fixes**
Part of a series of PRs to address kubernetes/community#598
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
Yang Li