Refactor newClient in ctr

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

cmd/ctr/checkpoint.go

@@ -19,19 +19,15 @@ var taskCheckpointCommand = cli.Command{
 		},
 	},
 	Action: func(context *cli.Context) error {
-		var (
-			ctx, cancel = appContext(context)
-			id          = context.Args().First()
-		)
-		defer cancel()
-
+		id := context.Args().First()
 		if id == "" {
 			return errors.New("container id must be provided")
 		}
-		client, err := newClient(context)
+		client, ctx, cancel, err := newClient(context)
 		if err != nil {
 			return err
 		}
+		defer cancel()
 		container, err := client.LoadContainer(ctx, id)
 		if err != nil {
 			return err