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>.

Use GetDryRunFlag to keep consistent

**What this PR does / why we need it**:
There's a cmd util GetDryRunFlag, but we still get 'dry-run' directly somewhere. This PR makes them consistent.

**Release note**:

```release-note
NONE
```