When we have purchase orders and we return some products to the
supplier, we now have the possibilty to set those moves as 'to refund'
and so the quantity received is decreased.
Because the feature 'to refund' already exists on the sale orders, we
will generalize it in the module 'stock_account' which is a dependency
of both 'sale_stock' and 'purchase' which are the both module that use
the feature 'to refund'.
Srushti Patel
49c159a906