[FIX] stock: unset warehouses

When 'Applicable on Warehouse' is set to `False`, the list of warehouses
should be emptied.

opw-803678

addons/stock/models/stock_location.py

@@ -183,6 +183,10 @@ class Route(models.Model):
             'domain': [('route_ids', 'in', self.ids)],
         }
 
+    @api.onchange('warehouse_selectable')
+    def _onchange_warehouse_selectable(self):
+        if not self.warehouse_selectable:
+            self.warehouse_ids = [(5, 0, 0)]
 
 class PushedFlow(models.Model):
     _name = "stock.location.path"