[FIX] stock_landed_costs: wrong `price_unit`update when multiple landed costs

`new_landed_cost_value` was added to `value` to recompute the
`price_unit` field. The issue is that when applying multiple landed
costs, `value` and `new_landed_cost_value` already contains the previous
landed costs, resulting in an erroneous `price_unit`.

This patch only adds `cost_to_add`, which is the current landed cost, to
`value`, which contains all the previous one.

To reproduce:
- Create a product FIFO / AUTOMATED
- Purchase 50 units@$2 and receive them (total value=$100)
- Add a landed cost of $100 on those 50 units and a landed cost of $50 on those 50 units
  (total value = $100+$100+$50)
- Sell 15 units (the value on move out =$75 > $75/15 = $5 unit cost)

The standard_price on the product = $7 while I expect to have $5

opw-1867002

0 files changed, 0 insertions, 0 deletions