Add missing ACTION_MEDIA_UNMOUNTED intent

When an SD card is removed without the user unmounting, the intent
ACTION_MEDIA_BAD_REMOVAL is fired but is missing the preceeding
ACTION_MEDIA_UNMOUNTED which is needed to keep UI consistency.

Now when bad media removal is detected an ACTION_MEDIA_UNMOUNTED
intent is sent before the ACTION_MEDIA_BAD_REMOVAL.

Change-Id: I133300f42bafab141351e796d7cfc13c15d133e0