**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.


addons/stock/stock.py
else:
                qty -= 1 if qty >= 1 else 0
                if qty == 0 and op_obj.product_qty == 0:
                    
                    self.unlink(cr, uid, [operation_id], context=context)
                    return False
            self.write(cr, uid, [operation_id], {'qty_done': qty}, context=context)
        else:
            
            picking_obj = self.pool.get("stock.picking")
            picking = picking_obj.browse(cr, uid, picking_id, context=context)
            values = {
                'picking_id': picking_id,
                'product_qty': 0,
                'location_id': picking.location_id.id, 
                'location_dest_id': picking.location_dest_id.id,
                'qty_done': 1,
                }
            for key in domain:
                var_name, dummy, value = key
                uom_id = False
                if var_name == 'product_id':
                    uom_id = self.pool.get('product.product').browse(cr, uid, value, context=context).uom_id.id
                update_dict = {var_name: value}
                if uom_id:
                    update_dict['product_uom_id'] = uom_id
                values.update(update_dict)
            operation_id = self.create(cr, uid, values, context=context)
        return operation_id
class stock_move_operation_link(osv.osv):