Bluetooth: Fix pair device command reply if adapter is powered off

According to Bluetooth Management API specification Pair Device Command
should generate command complete event on both success and failure.
This fix replying with command status (which lacks address info) when
adapter is powered off.

Signed-off-by: Szymon Janc <szymon.janc@tieto.com>
Acked-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>