Automatic merge from submit-queue (batch tested with PRs 34002, 38535, 37330, 38522, 38423)

Rename pet to stateful pods in statefulset e2e tests logs

Follow up https://github.com/kubernetes/kubernetes/pull/37243#discussion_r89193790

Note that only mentions of pet in logs are renamed, but not variable name, or file name / import path 

@foxish 

```release-note
NONE
```