fixed bug when editing a supplier order line

I had SQL errors when trying to edit a line in a supplier order.
fourn/commande/fiche.php was calling the updateline function with wrong parameters in some cases because it tried to fetch a Product object with a CommandeFournisseurLigne id.
Also, the CommandeFournisseurLigne fetch function requested from a field "local_localtax2" which doesn't exist in the database.