Automatic merge from submit-queue (batch tested with PRs 40964, 42967, 43091, 43115)

Update hack scripts to use godep v79 and ensure_godep_version

**What this PR does / why we need it**:
Based on #42965 and https://github.com/kubernetes/kubernetes/pull/42958#discussion_r105568318, this pins the godep version at v79, which should fix some issues when running godep in go1.8 local environments.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #42817

**Special notes for your reviewer**:
This should likely get the v1.6 milestone so that it can be merged into master. While I'm setting a default godep version, I'm continuing to use the local pins per this comment: https://github.com/kubernetes/kubernetes/pull/42965#issuecomment-285962723 .

**Release note**:

```release-note
NONE
```

cc: @sttts