Automatic merge from submit-queue (batch tested with PRs 38433, 36245)

Remove needless env var in OpenStack provider

**What this PR does / why we need it**:

If we use openstack provider to set up k8s cluster using kube-up script,
`TENANT_ID` environment variable is needed.
But to configure `TENANT_ID` is very annoying because this value is not static by each env.
This patch uses `TENANT_NAME` instead of `TENANT_ID`

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

**Special notes for your reviewer**:

**Release note**:

```release-note
```

Since `TENANT_NAME` is unique if we use keystone v2 api,
so `TENANT_ID` is not needed if `TENANT_NAME` is provided
to configure OpenStack provider.
And also to set `TENANT_ID` is annoying to develop, because
`TENANT_ID` is not static by each environment.
This patch remove dependency of `TENANT_ID` and simply use
`TENANT_NAME`.