QBluetoothDeviceDiscoveryAgent on Bluez does not distinguish Classic and LowEnergy search

QBluetoothDeviceDiscoveryAgent::start(DiscoveryMethod) permits the selection of the device search method. On Linux/Bluez the Qt implementation ignores the DiscoveryMethod parameter. The search is always done for all device types.

A recent addition to the Bluez Adapater1 interface permit this by adding the

SetDiscoveryFilter(dict filter)

functions. Qt's implementation should make use of this function. Since it is a recent addition the implementation must work for Bluez 5 versions which do not provide this function yet.