Address initial feedback from pr

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

execdriver/native/driver.go

@@ -2,7 +2,6 @@ package native
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"github.com/dotcloud/docker/execdriver"
 	"github.com/dotcloud/docker/pkg/cgroups"
@@ -22,10 +21,6 @@ const (
 	Version    = "0.1"
 )
 
-var (
-	ErrNotSupported = errors.New("not supported")
-)
-
 func init() {
 	execdriver.RegisterInitFunc(DriverName, func(args *execdriver.InitArgs) error {
 		var (
@@ -109,10 +104,13 @@ func (d *driver) Restore(c *execdriver.Command) error {
 	if err != nil {
 		return err
 	}
-	defer f.Close()
 	if _, err := fmt.Fscanf(f, "%d", &nspid); err != nil {
+		f.Close()
 		return err
 	}
+	f.Close()
+	defer os.Remove(p)
+
 	proc, err := os.FindProcess(nspid)
 	if err != nil {
 		return err