cleanup task: Expire all memberof targets when removing user
    
    Ticket:
    https://fedorahosted.org/sssd/ticket/2676
    
    When user is removed from cache during cleanup task, mark all
    his memberof targets as expired to refresh member/ghost
    attributes on next request.
    
    Reviewed-by: Pavel Reichl <preichl@redhat.com>
    (cherry picked from commit 4d8f0f92edccff1be52f2b505e76886708d32e26)