[1.2.X] Fixed #15869 - example AJAX code in CSRF docs fails sometimes for IE7...

[1.2.X] Fixed #15869 - example AJAX code in CSRF docs fails sometimes for IE7 or absolute same origin URLs

Thanks to nick for the report.

Backport of [16183] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@16185 bcc190cf-cafb-0310-a4f2-bffc1f526a37