[FIX] mrp_byproduct: take into account operation where byproduct gets produced

As the field is not shown in the view, it is just done
because the field is still there and easy to do.

addons/mrp/wizard/change_production_qty.py

@@ -63,6 +63,7 @@ class ChangeProductionQty(models.TransientModel):
                     wo.state = 'progress'
                 # assign moves; last operation receive all unassigned moves
                 operation = wo.operation_id
+                
 
                 # TODO: following could be put in a function as it is similar as code in _workorders_create
                 # TODO: only needed when creating new moves

addons/mrp_byproduct/models/mrp_production.py

@@ -23,6 +23,7 @@ class MrpProduction(models.Model):
                 'product_uom': sub_product.product_uom_id.id,
                 'location_id': source,
                 'location_dest_id': production.location_dest_id.id,
+                'operation_id': sub_product.operation_id.id,
                 'production_id': production.id,
                 'origin': production.name,
                 'unit_factor': qty1 / (production.product_qty - production.qty_produced),