obexd: terminate queued transfers properly
obexd: terminate queued transfers properly

Previous implementation of session_terminate_transfer assumed that the
transfer being terminated would always be the active one. However, it
should be possible to cancel any queued transfer using the D-Bus api.

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