Google sublocality should be city

[codemau5]

Google geocodes many addresses without locality, but with sublocality.
therefore i found that if no locality exists, the sublocality should be the city.

[ruscon]

Examples
https://github.com/alexreisner/geocoder/blob/master/lib/geocoder/results/google.rb#L20-L30
and
https://github.com/DenisCarriere/geocoder/blob/master/geocoder/google.py#L97-L103