`product.master` seems to always be `null` on
/api/v0/order_cycles/:id/products JSON response. That's because the
first of the underlying AR relation,
`order_cycle.variants_distributed_by(distributor)`, does not include
master variants. They are not in OC exchanges.
This means we avoid fetching all of the hub's variants every time we scope a product. Applies to every product loaded when displaying a shops's product list.
When products are sorted by name and two products have the same name,
their order is undefined. With pagination, two pages can have a
different order of products with the same name which then means that two
pages can return the same product.
Sorting by product id makes sure that the result is always in the same
order, for every page.
