Fix BluetoothToggle not showing in QuickSettings

Instead of attempting to get the BluetoothAdapter instance from a
SystemService (which fails) use the provided static singleton from the
BluetootAdapter see
{@link android.bluetooth.BluetoothAdapter#getDefaultAdapter}

Change-Id: Ic2f3c1e77132787d60d0214b7a3efb04cd0c42df