wifi: Allow Settings to retrieve country code

This makes getCountryCode behave like getFrequencyBand

This allows Settings to get/set country code like
it can for frequency band.

add aditional fixes to original implementation
and changes for 4.4

Change-Id: Id9f00d3a678642c6c142fd1511af820d729507a7
Merge remote-tracking branch 'upstream/kk4.4' into kk4.4