Automatic merge from submit-queue
Fixed a bug that causes k8s to delete all healthmonitors on your OpenStack tenant
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**What this PR does / why we need it**:
The OpenStack LBaaS v2 api does not support filtering health monitors by pool_id, so /lbaas/healthmonitors?pool_id=abc123 will always return all health monitors in your OpenStack tenant.
This presents a problem when, in the very next block of code, we loop over the list of monitorIDs and delete them one-by-one. This will delete all the health monitors in your tenant without warning.
Fortunately, we already got the healthmonitor IDs when we built the list of pools. Using those, we can delete only those healthmonitors associated with our pool(s).
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
The main issue here was the use of v2_monitors.List(lbaas.network, v2_monitors.ListOpts{PoolID: poolID}). This is trying to filter healthmonitors by pool_id, but that is not supported by the API. It creates a call like /lbaas/healthmonitors?pool_id=abc123. The API server ignores the pool_id parameter and returns a list of all healthmonitors (which k8s then tries to delete).
**Release note**:
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