BatteryStats: Don't log BluetoothScanTimer when it doesn't exist
BatteryStats: Don't log BluetoothScanTimer when it doesn't exist

Bug:27998591
Change-Id: I80ca8a2353141c16595b4be0b0aed195f40e366a

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base