**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
product = self.pool.get("product.product").browse(cr, uid, key[0], context=context)
            uom_id = product.uom_id.id
            qty_uom = qty
            if product_uom.get(key[0]):
                uom_id = product_uom[key[0]].id
                qty_uom = uom_obj._compute_qty(cr, uid, product.uom_id.id, qty, uom_id)
            val_dict = {
                'picking_id': picking.id,
                'product_qty': qty_uom,
                'product_id': key[0],
                'package_id': key[1],
                'lot_id': key[2],
                'owner_id': key[3],
                'location_id': key[4],
                'location_dest_id': key[5],
                'product_uom_id': uom_id,
            }
            if key[0] in prevals:
                prevals[key[0]].append(val_dict)
            else:
                prevals[key[0]] = [val_dict]
        
        processed_products = set()
        for move in [x for x in picking.move_lines if x.state not in ('done', 'cancel')]:
            if move.product_id.id not in processed_products:
                vals += prevals.get(move.product_id.id, [])
                processed_products.add(move.product_id.id)
        return vals
    @api.cr_uid_ids_context
    def open_barcode_interface(self, cr, uid, picking_ids, context=None):