Fix Device.CancelDiscovery() to cancel discover request.
Fix Device.CancelDiscovery() to cancel discover request.

CancelDiscovery() was not really replying and freeing memory allocated for
service discover witch cause Device.DiscoverServices to believe a response
is still pending.

silent-snowman/bluez,ComputeCycles/bluez,ComputeCycles/bluez,pkarasev3/bluez,ComputeCycles/bluez,silent-snowman/bluez,silent-snowman/bluez,mapfau/bluez,pkarasev3/bluez,mapfau/bluez,mapfau/bluez,pkarasev3/bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,pstglia/external-bluetooth-bluez,pstglia/external-bluetooth-bluez,silent-snowman/bluez,pkarasev3/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez