[1.2.X] Updated GeoDjango installation docs and spatial database template...

[1.2.X] Updated GeoDjango installation docs and spatial database template script for latest Ubuntu/Debian packages.

Backport of r15520 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15521 bcc190cf-cafb-0310-a4f2-bffc1f526a37