Revert to the May 2012 geoip db

The June 2012 db marks too many relays as country "A1".
Addresses bug 6334.

changes/revert-geoip-may2012

@@ -0,0 +1,6 @@
+  o Major bugfixes:
+    - Revert to the May 1 2012 Maxmind GeoLite Country database. In the
+      June 2012 database, Maxmind marked many Tor relays as country "A1",
+      which will cause risky behavior for clients that set EntryNodes
+      or ExitNodes. Addresses bug 6334; bugfix on 0.2.3.17-beta.
+