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`).
The geoip package only installs a GeoIP _library_ which is useless
without a GeoIP _database_.
The only package to currently install such a database is ntopng, which
manually downloads Maxmind's GeoLite Legacy files to a private location.
Provide these as a separate package so other packages can use them as
well.
