**Impacted versions:** 8.0

**Steps to reproduce:**
To reproduce it is necessary the fifo configuration in the assignation of quants in moves.

- Create a sale order with two lines of the same product, one of that line with a route that generate moves between warehouse.

<img width="1231" alt="skitch 65" src="https://cloud.githubusercontent.com/assets/11341058/24102907/d575a638-0d53-11e7-922e-a3f034d43e94.png">

The route used has three pull rules:

1. From Stock Warehouse_1 to Virtual Locations/Inter Company Transit
2. From Virtual Locations/Inter Company Transit to Stock Warehouse_2
3. From Stock Warehouse_2 to Customers

<img width="1224" alt="skitch 66" src="https://cloud.githubusercontent.com/assets/11341058/24103147/b7c2bfbc-0d54-11e7-955c-87247a10e0bd.png">

- Confirm the sale order. It must be created three pickings:

<img width="1226" alt="skitch 67" src="https://cloud.githubusercontent.com/assets/11341058/24103498/d90c9b38-0d55-11e7-97ff-f986df8cdd9b.png">

- Transfer first two pickings.

<img width="1230" alt="skitch 70" src="https://cloud.githubusercontent.com/assets/11341058/24104496/b7b0be8a-0d58-11e7-89a2-4331fceec1d8.png">

- Before transfer third picking, review that one move has reserved the quant correctly because was reserved from the previous pickings.

<img width="1215" alt="skitch 68" src="https://cloud.githubusercontent.com/assets/11341058/24103908/23952cc8-0d57-11e7-9346-bd48d7edb54a.png">

**Current behavior:**

When check availability of this third picking, the quant already reserved is moved to the other move.

<img width="1264" alt="skitch 69" src="https://cloud.githubusercontent.com/assets/11341058/24104056/8be11616-0d57-11e7-8763-a90507315b19.png">
 
**Expected behavior:**

When check availability of this third picking, the moves already reserved must not be altered.


context = context or {}
        res_id = super(stock_pack_operation, self).create(cr, uid, vals, context=context)
        if vals.get("picking_id") and not context.get("no_recompute"):
            self.pool.get("stock.picking").do_recompute_remaining_quantities(cr, uid, [vals['picking_id']], context=context)
        return res_id
    def action_drop_down(self, cr, uid, ids, context=None):
        ''' Used by barcode interface to say that pack_operation has been moved from src location 
            to destination location, if qty_done is less than product_qty than we have to split the
            operation in two to process the one with the qty moved
        '''
        processed_ids = []
        move_obj = self.pool.get("stock.move")
        for pack_op in self.browse(cr, uid, ids, context=None):
            if pack_op.product_id and pack_op.location_id and pack_op.location_dest_id:
                move_obj.check_tracking_product(cr, uid, pack_op.product_id, pack_op.lot_id.id, pack_op.location_id, pack_op.location_dest_id, context=context)
            op = pack_op.id
            if pack_op.qty_done < pack_op.product_qty:
                
                op = self.copy(cr, uid, pack_op.id, {'product_qty': pack_op.qty_done, 'qty_done': pack_op.qty_done}, context=context)
                self.write(cr, uid, [pack_op.id], {'product_qty': pack_op.product_qty - pack_op.qty_done, 'qty_done': 0}, context=context)
            processed_ids.append(op)
        self.write(cr, uid, processed_ids, {'processed': 'true'}, context=context)
    def create_and_assign_lot(self, cr, uid, id, name, context=None):