Automatic merge from submit-queue

Use provided VipPortID for OpenStack LB

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

When creating an OpenStack LoadBalancer, Kubernetes will search through the tenant trying to match the LB's VIP with a port. This is problematic because multiple ports may have the same fixed IP, therefore leading to routing inconsistencies. We should use the port ID provided by the LB's response body instead.

**Which issue this PR fixes**:

https://github.com/kubernetes/kubernetes/issues/43909

**Special notes for your reviewer**:

Since this involves non-deterministic testing, it'd be best if we can run this in a staging environment for a few days before merging (say until early next week).

**Release note**:
```release-note
Fixes issue during LB creation where ports where incorrectly assigned to a floating IP
```