**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.


res = {}
        quant_obj = self.pool["stock.quant"]
        uom_obj = self.pool["product.uom"]
        for line in self.browse(cr, uid, ids, context=context):
            quant_ids = self._get_quants(cr, uid, line, context=context)
            quants = quant_obj.browse(cr, uid, quant_ids, context=context)
            tot_qty = sum([x.qty for x in quants])
            if line.product_uom_id and line.product_id.uom_id.id != line.product_uom_id.id:
                tot_qty = uom_obj._compute_qty_obj(cr, uid, line.product_id.uom_id, tot_qty, line.product_uom_id, context=context)
            res[line.id] = tot_qty
        return res
    _columns = {
        'inventory_id': fields.many2one('stock.inventory', 'Inventory', ondelete='cascade', select=True),
        'location_id': fields.many2one('stock.location', 'Location', required=True, select=True),
        'product_id': fields.many2one('product.product', 'Product', required=True, select=True),
        'package_id': fields.many2one('stock.quant.package', 'Pack', select=True),
        'product_uom_id': fields.many2one('product.uom', 'Product Unit of Measure', required=True),
        'product_qty': fields.float('Checked Quantity', digits_compute=dp.get_precision('Product Unit of Measure')),
        'company_id': fields.related('inventory_id', 'company_id', type='many2one', relation='res.company', string='Company', store=True, select=True, readonly=True),
        'prod_lot_id': fields.many2one('stock.production.lot', 'Serial Number', domain="[('product_id','=',product_id)]"),
        'state': fields.related('inventory_id', 'state', type='char', string='Status', readonly=True),
        'theoretical_qty': fields.function(_get_theoretical_qty, type='float', digits_compute=dp.get_precision('Product Unit of Measure'),
                                           store={'stock.inventory.line': (lambda self, cr, uid, ids, c={}: ids, ['location_id', 'product_id', 'package_id', 'product_uom_id', 'company_id', 'prod_lot_id', 'partner_id'], 20),},
                                           readonly=True, string="Theoretical Quantity"),
        'partner_id': fields.many2one('res.partner', 'Owner'),
        'product_name': fields.related('product_id', 'name', type='char', string='Product Name', store={
                                                                                            'product.product': (_get_product_name_change, ['name', 'default_code'], 20),
                                                                                            'stock.inventory.line': (lambda self, cr, uid, ids, c={}: ids, ['product_id'], 20),}),
        'product_code': fields.related('product_id', 'default_code', type='char', string='Product Code', store={
                                                                                            'product.product': (_get_product_name_change, ['name', 'default_code'], 20),