use the default recovery UI
use the default recovery UI

The key handling we use for hammerhead is now the recovery default; we
no longer need a subclass of ScreenRecoveryUI.

Change-Id: Ibe0236d4046e99c36f6d21b8621a071bfc758e1c

maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead,maruos/android_device_lge_hammerhead