Update the roam status to headset

This change makes sure that roam status
change is updated to headset immediately
as soon as it is changed. With this, we will
not wait to update the roam status till network
service state changed.

This fixes a PTS test case. Notmally a roaming
state change would be accompanied by a service
state change.

Change-Id: Ib30a69e58ee81e67986ffde52093e5f37315f814