display-access-file: maintain FamilyLocal entry for backward compatibility
    
    commit 0fccf4e0671e49f6e57d0135c97344973c042b23 swapped out the
    FamilyLocal auth cookie for a FamilyWild auth cookie, because the
    latter is more resilient to hostname changes.  Unfortunately,
    not all of the tooling accepts FamilyWild cookies (in particular the
    xauth command), so things like su broke.
    
    This commit changes the code to have a FamilyWild and FamilyLocal
    cookie.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=690562