Bluetooth-OPP: Keep Notification thread running when transfer is via NFC

OPP notification thread should be running when file transfer is
via NFC because NFC module is listening to TRANSFER_PROGRESS intent
from notification. Otherwise, after 20 seconds NFC will turn OFF BT
and cause transfer failure.

CRs-Fixed: 762328
Change-Id: Ibf40439f1c304e878eb90bfa805d6994eb878c83