geolite-legacy: use correct local naming scheme

Following http://dev.maxmind.com/geoip/legacy/install/city/:

  "Then rename the *.dat file to GeoIP.dat, GeoIPRegion.dat, or
   GeoIPCity.dat, for the GeoIP Country, Region or City databases,
   respectively."

Using the default "GeoLiteCity*.dat" name caused ipv6calc to miss it
(verified using `ipv6calc -vv`).