fix double-lock

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

daemon/graphdriver/aufs/aufs.go

@@ -288,9 +288,7 @@ func (a *Driver) Remove(id string) error {
 		return err
 	}
 	if m != nil {
-		a.Lock()
 		delete(a.active, id)
-		a.Unlock()
 	}
 	return nil
 }

daemon/graphdriver/aufs/mount.go

@@ -12,7 +12,7 @@ import (
 // Unmount the target specified.
 func Unmount(target string) error {
 	if err := exec.Command("auplink", target, "flush").Run(); err != nil {
-		logrus.Errorf("Couldn't run auplink before unmount: %s", err)
+		logrus.Errorf("Couldn't run auplink before unmount %s: %s", target, err)
 	}
 	if err := syscall.Unmount(target, 0); err != nil {
 		return err