User data deletion by anoynmous users in Zope

Zope AccessControl provides a general security framework for use in Zope. In affected versions anonymous users can delete the user data maintained by an `AccessControl.userfolder.UserFolder` which may prevent any privileged access. This problem has been fixed in version 7.2. Users are advised to upgrade. Users unable to upgrade may address the issue by adding `data__roles__ = ()` to `AccessControl.userfolder.UserFolder`.