Comment 8 for bug 1410034

I've been looking into this and it is my understanding that this is a misconception in the implementation.
API clearly states for os-quota-sets delete: "Deletes quotas for a tenant so the quotas revert to default values"
It doesn't say anything about deleting usage or reservations which, as you guys mentioned, are being deleting right now.

If we want to have a way to clear/reset usage/reservations we should have a look into it, although I can't think right now of a good reason why we would need it. For now we should fix this.