Fix the behaviour of the DiscoverCharacteristics method
Fix the behaviour of the DiscoverCharacteristics method

The previous behaviour could lead to some problems, as it returned
as soon as possible. To avoid problems we return just after as the
characteristics are discovered, and to save a few round trips we
return the path of all characteristics that belong to this service.

After this method return it will try to read the characteristics
values.

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