delivery: global name 'except_osv' is not defined if a carrier has no valid grid defined

Instead of jsut displaying the proper error message, it when trying to add a delivery cost through the wirzard in a quotation, if the carrier has no grid list defined, we get this ugly stack:

  File "/home/rvalyi/DEV/openobject_trunk/openobject-server/bin/netsvc.py", line 387, in run
    r = m(*msg[2:])
  File "/home/rvalyi/DEV/openobject_trunk/openobject-server/bin/service/web_services.py", line 422, in execute
    return self._execute(db, uid, wiz_id, datas, action, context)
  File "/home/rvalyi/DEV/openobject_trunk/openobject-server/bin/service/web_services.py", line 402, in _execute
    return wiz.execute(db, uid, self.wiz_datas[wiz_id], action, context)
  File "/home/rvalyi/DEV/openobject_trunk/openobject-server/bin/wizard/__init__.py", line 170, in execute
    res = self.execute_cr(cr, uid, data, state, context)
  File "/home/rvalyi/DEV/openobject_trunk/openobject-server/bin/wizard/__init__.py", line 73, in execute_cr
    action_res = action(self, cr, uid, data, context)
  File "/home/rvalyi/DEV/openobject_trunk/openobject-addons/delivery/wizard/delivery_sale_order.py", line 76, in _delivery_set
    'price_unit': grid_obj.get_price(cr, uid, grid.id, order, time.strftime('%Y-%m-%d'), context),
  File "/home/rvalyi/DEV/openobject_trunk/openobject-addons/delivery/delivery.py", line 108, in get_price
    return self.get_price_from_picking(cr, uid, id, total,weight, volume, context)
  File "/home/rvalyi/DEV/openobject_trunk/openobject-addons/delivery/delivery.py", line 127, in get_price_from_picking
    raise except_osv(_('No price avaible !'), _('No line matched this order in the choosed delivery grids !'))
NameError: global name 'except_osv' is not defined

The fix should be simple: just replace that deprecated except_osv API call! Then it will be more obvious for the users why the delievry cost can't be added unless he defines a grid.

Raphaël Valyi