BluetoothAdapter: throw when system server is dead

Calling the manager service must never failed as the manager service
cannot be turned off.
If a remote exception occurs that mean the whole system is dead and we
have to rethrow the exception

Test: m .
Bug: 311772251
Flag: Exempt refactor
Change-Id: I3ab9d5f06c05f26afbc5ad94aaef2db0aa3a8126