// of a rebalance, was expanded can cause z.rebalMeta to be outdated
// due to a missing new pool. This function tries to handle this
// scenario, albeit rare it seems to have occurred in the wild.
//
// since we do not explicitly disallow it, but it is okay for them
// expand and then we continue to rebalance.
func (z *erasureServerPools) updateRebalanceStats(ctx context.Context) error {
	var ok bool