Clean up ReplicaSets

[mateusoliveira43]

As documented, ReplicaSets can become left out in cluster

https://github.com/openshift/oadp-operator/blob/master/docs/install_olm.md#verify-install

This can reproduced when testing upgrades

NAME                                                          DESIRED   CURRENT   READY   AGE
replicaset.apps/openshift-adp-controller-manager-686685cc8f   1         1         1       4m33s
replicaset.apps/openshift-adp-controller-manager-77c584bf8b   0         0         0       6m33s
replicaset.apps/velero-5fdf7d65df                             1         1         1       118s
replicaset.apps/velero-6bf5469f9c                             0         0         0       5m40s

[kaovilai]

These are by design by kube to be left over. You can set following if you don't like seeing "historical" replicasets.

Clean up Policy
You can set .spec.revisionHistoryLimit field in a Deployment to specify how many old ReplicaSets for this Deployment you want to retain. The rest will be garbage-collected in the background. By default, it is 10.