Automatic merge from submit-queue (batch tested with PRs 59106, 58985, 59068, 59120, 59126). 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>.
Integration tests for envelop encryption/decryption of secrets.
**What this PR does / why we need it**:
Provides integration tests between KubeAPI Server and etcd (in the context of encrypting secrets at rest). Concretely, tests assert that:
1. Secrets are stored encrypted in ectcd
2. Secrets are decrypted on reads
when --experimental-encryption-provider-config flag is passed to KubeAPI server.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
This PR does not address any specific issues, but rather provides integration testing coverage for the [encrypt/encryption](https://github.com/kubernetes/kubernetes/blob/release-1.9/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/envelope.go) feature.
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```