Problem with Sign-Out in Sharepoint 2013

Hi,

   I enabled claims based authentication in Sharepoint 2013 and it works fine. Unfortunatelly when I click Sign-Out button I got error like described in this thread:

http://blog.lekman.com/2012/07/resolved-sign-out-from-forms.html

I don't have custom login page so I don't know where I can put this code to clear session or cookies ? Please help if anybody know whatever about it. Thanx.