**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 = []
        for route in self.browse(cr, uid, ids, context=context):
            res += [x.id for x in route.push_ids]
        return res
    _columns = {
        'name': fields.char('Operation Name', required=True),
        'company_id': fields.many2one('res.company', 'Company'),
        'route_id': fields.many2one('stock.location.route', 'Route'),
        'location_from_id': fields.many2one('stock.location', 'Source Location', ondelete='cascade', select=1, required=True),
        'location_dest_id': fields.many2one('stock.location', 'Destination Location', ondelete='cascade', select=1, required=True),
        'delay': fields.integer('Delay (days)', help="Number of days to do this transition"),
        'picking_type_id': fields.many2one('stock.picking.type', 'Type of the new Operation', required=True, help="This is the picking type associated with the different pickings"), 
        'auto': fields.selection(
            [('auto','Automatic Move'), ('manual','Manual Operation'),('transparent','Automatic No Step Added')],
            'Automatic Move',
            required=True, select=1,
            help="This is used to define paths the product has to follow within the location tree.\n" \
                "The 'Automatic Move' value will create a stock move after the current one that will be "\
                "validated automatically. With 'Manual Operation', the stock move has to be validated "\
                "by a worker. With 'Automatic No Step Added', the location is replaced in the original move."
            ),
        'propagate': fields.boolean('Propagate cancel and split', help='If checked, when the previous move is cancelled or split, the move generated by this move will too'),
        'active': fields.boolean('Active', help="If unchecked, it will allow you to hide the rule without removing it."),
        'warehouse_id': fields.many2one('stock.warehouse', 'Warehouse'),
        'route_sequence': fields.related('route_id', 'sequence', string='Route Sequence',