Comment 2 for bug 1716706

The other thing we have to handle here is if we count build_requests, we have to avoid double counting where the build_request and instance exist at the same time, which we know is the case when we recheck quota in conductor (after the instances are created in the cells but before the build requests are deleted). So only the API service can count build_requests *and* instances in cells, but conductor can only count instances in cells.