**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
state = 'waiting'
            
            elif move.split_from:
                move2 = move.split_from
                while move2 and state != 'waiting':
                    if move2.move_orig_ids:
                        state = 'waiting'
                    move2 = move2.split_from
            states[state].append(move.id)
            if not move.picking_id and move.picking_type_id:
                key = (move.group_id.id, move.location_id.id, move.location_dest_id.id)
                if key not in to_assign:
                    to_assign[key] = []
                to_assign[key].append(move.id)
        moves = [move for move in self.browse(cr, uid, states['confirmed'], context=context) if move.procure_method == 'make_to_order']
        self._create_procurements(cr, uid, moves, context=context)
        for move in moves:
            states['waiting'].append(move.id)
            states['confirmed'].remove(move.id)
        for state, write_ids in states.items():
            if len(write_ids):
                self.write(cr, uid, write_ids, {'state': state}, context=context)
        
        for key, move_ids in to_assign.items():
            procurement_group, location_from, location_to = key
            self._picking_assign(cr, uid, move_ids, procurement_group, location_from, location_to, context=context)
        moves = self.browse(cr, uid, ids, context=context)
        self._push_apply(cr, uid, moves, context=context)
        return ids
    def force_assign(self, cr, uid, ids, context=None):