CRM-14249 - fix fatal error when anonymous user accesses civicrm/mailing/view.

----------------------------------------
* CRM-14249: Can't view public mailings when logged out
  http://issues.civicrm.org/jira/browse/CRM-14249
Merge pull request #2547 from davecivicrm/CRM-14249

CRM-14249 - fix fatal error when anonymous user accesses civicrm/mailing...