This releases the underlying resource sooner and ensures that another consumer
can get scheduled without being influenced by a decision that was made for the
previous consumer.
An alternative would have been to have the apiserver trigger the deallocation
whenever it sees the `status.reservedFor` getting reduced to zero. But that
then also triggers deallocation when kube-scheduler removes the last
reservation after a failed scheduling cycle. In that case we want to keep the
claim allocated and let the kube-scheduler decide on a case-by-case basis which
claim should get deallocated.