Inventory correction moves are calculated based on current date and not inventory date

When doing a stocktaking and fill an inventory, moves are calculated based on current date and not on inventory creation date.

eg:
2011/12/31 total stock moves = 100
2012/01/01 stocktaking = 90
2012/01/02 out product move for 5
2012/01/03 inventory for 90 is posted (with creation date = 1/1)

Done correction move is 100 - 90 + 5 = 5
Correct correction move is 100 - 90 = 10

This is because following line in stock.py/stock_inventory/action_confirm seems incorrect and currently do ask the available quantity up to date (to_date context field):
# product_context.update(uom=line.product_uom.id, date=inv.date, prodlot_id=line.prod_lot_id.id)
                product_context.update(uom=line.product_uom.id, to_date=inv.date, prodlot_id=line.prod_lot_id.id)#EC