[FIX] website_sale: customer_lead in the shop

Let's consider a product P with a sale_delay = 10
When creating a SO for P in the backend, the customer_lead is correctly
set to 10. But when creating a SO in the shop for P, the customer_lead
was not correctly set.

opw:1880577

addons/website_sale/models/sale_order.py

@@ -105,6 +105,7 @@ class SaleOrder(models.Model):
             'order_id': order_id,
             'product_uom': product.uom_id.id,
             'price_unit': pu,
+            'customer_lead': product.sale_delay,
         }
 
     @api.multi