Disable Bluetooth if BLE was disabled while enabling

* Call onBrEdrDown if BLE app count is 0 when entering BLE_ON state and
  the Bluetooth ON was triggered via enableBle().
  This fixes an issue that Bluetooth automatically turns ON if gms calls
  enableBle() then disableBle() in a short time.
* Fix a deadlock bug that acquires writeLock in a readLock.

Bug: 153767389
Bug: 155950370
Test: Manual
Change-Id: I4f92581465de81ffe9b45fb042b5cc43e5ab4136