Fixed #14494 -- Cleanup and typo in tutorial 4, introduced by class-based view...

Fixed #14494 -- Cleanup and typo in tutorial 4, introduced by class-based view changes. Thanks to Andrews Medina for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14278 bcc190cf-cafb-0310-a4f2-bffc1f526a37