w2grid: Don't add double break if search field is hidden

With 
        show: {
            header: true,
            footer: true,
            toolbar: true,
            toolbarSave: true,
            toolbarAdd: true,
            toolbarDelete: true,
            toolbarSearch: false,
        },
there were two toolbar separators between the refresh/show/hide buttons an the add/delete buttons, looking not so nice.