Move supervisor to it's own package

It allows to keep main namespace cleaner

Signed-off-by: Alexander Morozov <lk4d4@docker.com>

supervisor/delete.go

@@ -0,0 +1,37 @@
+package supervisor
+
+import (
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/containerd/runtime"
+)
+
+type DeleteEvent struct {
+	s *Supervisor
+}
+
+func (h *DeleteEvent) Handle(e *Event) error {
+	if i, ok := h.s.containers[e.ID]; ok {
+		if err := h.deleteContainer(i.container); err != nil {
+			logrus.WithField("error", err).Error("containerd: deleting container")
+		}
+		if i.copier != nil {
+			if err := i.copier.Close(); err != nil {
+				logrus.WithField("error", err).Error("containerd: close container copier")
+			}
+		}
+		h.s.notifySubscribers(&Event{
+			Type:   ExitEventType,
+			ID:     e.ID,
+			Status: e.Status,
+			Pid:    e.Pid,
+		})
+		ContainersCounter.Dec(1)
+		h.s.containerGroup.Done()
+	}
+	return nil
+}
+
+func (h *DeleteEvent) deleteContainer(container runtime.Container) error {
+	delete(h.s.containers, container.ID())
+	return container.Delete()
+}