MNCs not in carrier_list can get the wrong MNC value

Mobile Network Codes that belong to SIM cards not specified
in carrier_list sometimes get the wrong MNC value.

This change aims to improve the likelihood of a
correct MNC.

Test: Install an RRO with apns.xml and look at the DB.
Bug: 186542894
Change-Id: I1dbccf9d75a7a8ae896ca483935bc5e007843e75
Merged-in: I1dbccf9d75a7a8ae896ca483935bc5e007843e75
1 file changed