title: domain -> subdomain - passing session data
body: <p>Howdy, having a little trouble here.
  I have domain.co.uk setting a session. When I click on a link on domain.co.uk to go to sub.domain.co.uk the session is not being read.</p>
  
  <p>I have altered session.cookie_domain to .domain.co.uk not still not working. Is there anything else that needs changing?</p>
  
  <p>Regards,
  me. </p>