Fixed #10855: Reference doc on creating superusers in the tutorial at the...

Fixed #10855: Reference doc on creating superusers in the tutorial at the point where an account is needed, so that readers who neglected to create one earlier (or who forgot the password) don't get stuck or think they have to start all over.  Thanks cwolf127 and timo.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@10810 bcc190cf-cafb-0310-a4f2-bffc1f526a37