**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.


negative_vals['qty'] = float_round(-qty, precision_rounding=rounding)
            negative_vals['cost'] = price_unit
            negative_vals['negative_move_id'] = move.id
            negative_vals['package_id'] = src_package_id
            negative_quant_id = self.create(cr, SUPERUSER_ID, negative_vals, context=context)
            vals.update({'propagated_from_id': negative_quant_id})
        
        quant_id = self.create(cr, SUPERUSER_ID, vals, context=context)
        return self.browse(cr, uid, quant_id, context=context)
    def _quant_split(self, cr, uid, quant, qty, context=None):
        context = context or {}
        rounding = quant.product_id.uom_id.rounding
        if float_compare(abs(quant.qty), abs(qty), precision_rounding=rounding) <= 0: 
            return False
        qty_round = float_round(qty, precision_rounding=rounding)
        new_qty_round = float_round(quant.qty - qty, precision_rounding=rounding)
        
        cr.execute("""SELECT move_id FROM stock_quant_move_rel WHERE quant_id = %s""", (quant.id,))
        res = cr.fetchall()
        new_quant = self.copy(cr, SUPERUSER_ID, quant.id, default={'qty': new_qty_round, 'history_ids': [(4, x[0]) for x in res]}, context=context)
        self.write(cr, SUPERUSER_ID, quant.id, {'qty': qty_round}, context=context)
        return self.browse(cr, uid, new_quant, context=context)
    def _get_latest_move(self, cr, uid, quant, context=None):
        move = False
        for m in quant.history_ids:
            if not move or m.date > move.date:
                move = m
        return move
    @api.cr_uid_ids_context
    def _quants_merge(self, cr, uid, solved_quant_ids, solving_quant, context=None):