Merge pull request #198 from jkangas/next

Request for pulling prevention of modem data reseting if modem is not registered to next branch
[rilmodem] Check if really network registration status is really searching

If connection drops to searching and only voice call registration
status changes to roaming, with current implementation it is possible
to get through roaming allowed check in core. This prevents it.

Signed-off-by: Jussi Kangas <jussi.kangas@oss.tieto.com>