Impacted versions: 10.0

Steps to reproduce:
1. Create pos order with two products.
2. One of the products, must be type= Stockable Product and quantity=0.
3. Pay order.
4. check order --> extra info --> picking
5. picking state = Waiting Availability  

Current behavior:
picking State = Waiting Availability

Expected behavior:
picking State  = Done
[As in v9.0](https://youtu.be/X_R_jHZdYb8)

Video/Screenshot link (optional):
https://youtu.be/eWCe6juEcvw

if self.product_id:
            if not self.order_id.pricelist_id:
                raise UserError(_('You have to select a pricelist in the sale form !'))
            price = self.price_unit * (1 - (self.discount or 0.0) / 100.0)
            self.price_subtotal = self.price_subtotal_incl = price * self.qty
            if (self.product_id.taxes_id):
                taxes = self.product_id.taxes_id.compute_all(price, self.order_id.pricelist_id.currency_id, self.qty, product=self.product_id, partner=False)
                self.price_subtotal = taxes['total_excluded']
                self.price_subtotal_incl = taxes['total_included']
    @api.multi
    def _get_tax_ids_after_fiscal_position(self):
        for line in self:
            line.tax_ids_after_fiscal_position = line.order_id.fiscal_position_id.map_tax(line.tax_ids, line.product_id, line.order_id.partner_id)
class PosOrderLineLot(models.Model):