The new support for queryset augmentation for data display purposes

didn't work quite right. It applied to the initial query, but we'd then

end up generating a new query based on the IDs returned from that query.

That new query was augmented the old-fashioned way, but not the new way.
This change fixes that up so that we properly augment the final

data-fetching queryset.

Unit tests pass.
Tested this with some in-progress datagrid fixes in Review Board.