Telephony: Don't show as roaming if new state isn't in service.

  We can receive a regCode which states that we're currently roaming
  when transitioning between operator registrations. However, if the
  new service state doesn't have us registering to an operator and
  being out of service, then showing the device as "roaming" may not
  be the correct behavior. Instead, always show device as not roaming
  if the new service state is an invalid registration.

TICKET: CYNGNOS-2209

Change-Id: I6f49175fcebb522909e1114e74d16323f518ba9a
(cherry picked from commit 6ff91ffb)