correcting get_active_states()

It was missing 'for k' in the get_active_states.

```
Traceback (most recent call last):
  File "/home/dwlee/rocon_ws/src/rocon_taskcoordinator/task_master/task_manager/scripts/cafe_manager.py", line 863, in <module>
    main()
  File "/home/dwlee/rocon_ws/src/rocon_taskcoordinator/task_master/task_manager/scripts/cafe_manager.py", line 850, in main
    sis.start()	
  File "/home/dwlee/rocon_ws/src/executive_smach/smach_ros/src/smach_ros/introspection.py", line 274, in start
    self.construct(self._server_name, self._state, self._path)
  File "/home/dwlee/rocon_ws/src/executive_smach/smach_ros/src/smach_ros/introspection.py", line 295, in construct
    proxy._publish_status("Initial state")
  File "/home/dwlee/rocon_ws/src/executive_smach/smach_ros/src/smach_ros/introspection.py", line 220, in _publish_status
    self._container.get_active_states(),
  File "/home/dwlee/rocon_ws/src/executive_smach/smach/src/smach/concurrence.py", line 376, in get_active_states
    return [label for (label,outcome) in ((k,self._child_outcomes[k]) in self._child_outcomes) if outcome is None]
NameError: global name 'k' is not defined

```
Merge pull request #17 from jihoonl/patch-1

correcting get_active_states()