Bluetooth: Not allow Blank BT device name.

Add empty string check for BT device name
and not enable ok button until entered
device name is not empty.

Change-Id: Ib7c460bee5c8d86d13acd66d228279dd1a240c25
CRs-fixed: 471158
Bluetooth: Handle pairing Cancel intent.

Receive Pairing cancel intent and clear pairing request
from notification window.

CRs-fixed: 463362

Change-Id: I63c9299edca4356485f26cbc6332e3be9bdfbf17