Bluetooth: Adds check to verify Bluetooth adapter state

This checks whether bluetooth is turned ON or not in BLE
start scan process.BLE scan apis are called from applications
so need to check if BT adapter state is ON to avoid Bluetooth
crash

CRs-fixed: 649274
Change-Id: Ic075e1560bba2cabbfac2e1477932f9ad3144067
Bluetooth: Change userhandle to current from ALL

Change to a user handle to indicate the current
user of the device instead of ALL to avoid the
force close error in bluetooth.

Change-Id: I72e5feba6616a48ef8590b6965ec1d94f27b7dca
CRs-fixed: 742926
Bluetooth: Enforce BT state check during GATT close/disconnect

Enforce BT state check when BLE Apps call into GATT to handle scenarios in which
delayed call from BLE App to disconnect/close comes after the BT is OFF

CRs-Fixed: 759852
Change-Id: Iaf7004cdd4fe52e64c48838f6ed918e1d25f5a1e