Fix using invalid data from previous headset connection
Fix using invalid data from previous headset connection

Data from previous connection should be reset once disconnected, to fix
this a new structure is introduced called headset_slc which represents
the Service Level Connection and hold the connection data which is freed
when disconnected.

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