Bluetooth: Setting bluetooth.isEnabled on BT state change

btwlancoex process starts based on the bluetooth.isEnabled
property which is used to indicate Bluetooth on/off. If BT is
already turned on before rebooting the phone. btwlancoex process
does not start, As  property is not getting set, Even though
bluetooth is turned on successfully after rebooting phone, if
bluedroid stack is enabled. Setting the property from adapter
state,Once BT state change(ON or OFF) is recieved from
abstraction layer in bluedroid stack.
CRs-Fixed: 496729

Change-Id: Ieae4356064e98953287c842e0c60c76c56e7f1c6