core: Start LE scanning when a device requests
core: Start LE scanning when a device requests

This patch enables the LE scanning when a device requires connection and
there isn't discovery sessions, triggering the General Connection
Establishment Procedure.

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