Set lot on inventory move of ShipmentOut

If lot is set on the outgoing move, it should be set also on
the inventory move to allow proper synchronization.

issue8648
review285941002

stock.py

@@ -160,6 +160,12 @@ class ShipmentIn(metaclass=PoolMeta):
 class ShipmentOut(metaclass=PoolMeta):
     __name__ = 'stock.shipment.out'
 
+    def _get_inventory_move(self, outgoing_move):
+        move = super()._get_inventory_move(outgoing_move)
+        if move and outgoing_move.lot:
+            move.lot = outgoing_move.lot
+        return move
+
     def _sync_move_key(self, move):
         return super()._sync_move_key(move) + (('lot', move.lot),)