Cannot enable Bluetooth after using airplane and Bluetooth tethering sequentially

The root cause is we can't unbind blue service when bluetooth isnot disbaled
Otherwise the bluedroid stack will be out of sync with bluetooth service
only unbind bluetoothservice, when bluetooth is at OFF state.

bug 7376846

Change-Id: If5a11926f77a1ac29e75cdddbf5e90d492179f43