Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
kubelet/cm: remove unneeded fork of 'cat'
Reading a file in Go is perfectly possible without invoking cat.
I also removed an outdated comment.
This is meant to be a trivial/minor code cleanup, nothing more.
```release-note
NONE
```
eabc7a3553