UNKONWN is also a service state

When a service that in part of a business rules is in UNKNOWN state, i get this exception in scheduler

2013-10-14 08:58:01,072 [1381733881] Critical : I got an unrecoverable error. I have to exit
2013-10-14 08:58:01,073 [1381733881] Critical : You can log a bug ticket at https://github.com/naparuba/shinken/issues/new to get help
2013-10-14 08:58:01,097 [1381733881] Critical : Back trace of it: Traceback (most recent call last):
  File "/opt/shinken-sandbox/shinken/daemons/schedulerdaemon.py", line 405, in main
    self.do_mainloop()
  File "/opt/shinken-sandbox/shinken/daemon.py", line 244, in do_mainloop
    self.do_loop_turn()
  File "/opt/shinken-sandbox/shinken/daemons/schedulerdaemon.py", line 267, in do_loop_turn
    self.sched.run()
  File "/opt/shinken-sandbox/shinken/scheduler.py", line 1546, in run
    f()
  File "/opt/shinken-sandbox/shinken/scheduler.py", line 924, in manage_internal_checks
    c.ref.manage_internal_check(c)
  File "/opt/shinken-sandbox/shinken/objects/schedulingitem.py", line 1494, in manage_internal_check
    c.output = self.get_business_rule_output()
  File "/opt/shinken-sandbox/shinken/objects/schedulingitem.py", line 1453, in get_business_rule_output
    status = mapping[self.business_rule.get_state()]
KeyError: 3