'Deletes a snapshot of a volume attached to a specified instance.
The counter action to this is :func:`volume_snapshot_create`
:param nova.context.RequestContext context:
The security context.
:param nova.objects.instance.Instance instance:
The instance that has the volume attached.
:param uuid volume_id:
Attached volume associated with the snapshot
:param uuid snapshot_id:
The snapshot to delete.
:param dict delete_info:
Volume backend technology specific data needed to be able to
complete the snapshot.  For example, in the case of qcow2 backed
snapshots, this would include the file being merged, and the file
being merged into (if appropriate).
:return: None'

def volume_snapshot_delete(self, context, instance, volume_id, snapshot_id, delete_info):

    raise NotImplementedError()
