db: inline calls to get_all

This method saves basically no typing, compared to "query().all()".
Additionally, "all()" returns a list, forcing all records to be loaded
into a memory at the same time, but some callers just need to iterate
over the objects one at a time, in which case "query()" alone is more
efficient. In one case, the caller can even use "count()" and avoid
loading any objects from the database at all.