DO NOT MERGE - Set country code even when device is not registered on network

Extends the functionality of getNetworkCountryIso to support
no SIM/no service case. When no SIM/no service, it returns
the country code of nearby network (unregistered but cell info
is available to the device).

Test: Manual
Bug: 64335394
Change-Id: I3054a300aa569a0e9c99934970a2bdb3b9fcac41