Some tweaks to statistics.
Changes to directory request statistics: - Rename GEOIP statistics to DIRREQ statistics, because they now include more than only GeoIP-based statistics, whereas other statistics are GeoIP-dependent, too. - Rename output file from geoip-stats to dirreq-stats. - Add new config option DirReqStatistics that is required to measure directory request statistics. - Clean up ChangeLog. Also ensure that entry guards statistics have access to a local GeoIP database.