[FIX] stock: let resupply from warehouse work

If you set WH B to be resupplied from WH A, then the scheduler will
generate a procurement with warehouse_id = B and location_id = B.stock.
Running the procurement will find the resupply rule, and this will
create another procurement with warehouse_id = A and location_id =
transit location.

However, without this patch, the resupply route is not part of the
route_ids of warehouse A, and so the 2nd procurement goes in exception
because if cannot find a rule (the search will force a rule linked to a
route which is part of A.route_ids).

Closes #7956