Remove go-metrics

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

supervisor/delete.go

@@ -19,7 +19,6 @@ type DeleteTask struct {
 
 func (s *Supervisor) delete(t *DeleteTask) error {
 	if i, ok := s.containers[t.ID]; ok {
-		start := time.Now()
 		if err := s.deleteContainer(i.container); err != nil {
 			logrus.WithField("error", err).Error("containerd: deleting container")
 		}
@@ -35,8 +34,6 @@ func (s *Supervisor) delete(t *DeleteTask) error {
 				PID:       t.PID,
 			})
 		}
-		ContainersCounter.Dec(1)
-		ContainerDeleteTimer.UpdateSince(start)
 	}
 	return nil
 }