Commit id '162efa1a' added support hotplug a redirdev, but
did not add the hot unplug. This patch will add that support
to allow usage of the detach-device --live on the device.
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NChen Hanxiao <chenhanxiao@gmail.com>