// DeleteVolumeNode removes the given volume and node from the underlying
	// store indicating the specified volume is no longer attached to the
	// specified node.
	// If the volume/node combo does not exist, this is a no-op.
	// If after deleting the node, the specified volume contains no other child
	// nodes, the volume is also deleted.
	DeleteVolumeNode(volumeName v1.UniqueVolumeName, nodeName types.NodeName)