Bluetooth: Use correct previous state while moving to STATE_OFF

This change takes care of the previous state saved in the broadcast
intent while BT turns Off in absence of any BLE always ON app.
When bluetooth moved from STATE_BLE_TURNING_OFF to TURN_OFF
the previous state will be fed into the intent as TURNING_OFF
because the external apps such as CTS are not aware of the
LE_TURNING_OFF state

CRs-Fixed: 921438
Change-Id: I5f561d5b68768790f30cdbc605f378aeace9ad46