Fixed #9083 -- Improved get_admin_log template tag so that it doesn't run a...

Fixed #9083 -- Improved get_admin_log template tag so that it doesn't run a separate SQL query for every record in the 'history' sidebar on the admin homepage. Thanks for the patch, santip

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9045 bcc190cf-cafb-0310-a4f2-bffc1f526a37