Refactor checkpoint information

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

checkpoint.go

@@ -11,3 +11,15 @@ func (h *CreateCheckpointEvent) Handle(e *Event) error {
 	}
 	return container.Checkpoint(*e.Checkpoint)
 }
+
+type DeleteCheckpointEvent struct {
+	s *Supervisor
+}
+
+func (h *DeleteCheckpointEvent) Handle(e *Event) error {
+	container, ok := h.s.containers[e.ID]
+	if !ok {
+		return ErrContainerNotFound
+	}
+	return container.DeleteCheckpoint(e.Checkpoint.Name)
+}