Handle the case where owner does not have view permission on object. It cannot...

Handle the case where owner does not have view permission on object. It cannot be handled with a NULL nicely, because NOT(NULL) AND [...] is always false in SQL, and it is required to negate conditions automaticaly for worklists.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@18327 20353a03-c40f-0410-a6d1-a30d3c3de9de