Fixed #11245, #11246 -- Fixed validity check of `GeoIP` pointers and leaking...

Fixed #11245, #11246 -- Fixed validity check of `GeoIP` pointers and leaking of their references; also clarified initialization, fixed a stale test, added comments about version compatibility, and did some whitespace cleanup.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@10979 bcc190cf-cafb-0310-a4f2-bffc1f526a37