Remove hrpsys_gazebo_tutorials from rtmros_gazebo

hrpsys_gazebo_tutorials is moved from rtmros_gazebo to rtmros_tutorials.
https://github.com/start-jsk/rtmros_gazebo/issues/129#issuecomment-58307181
https://github.com/start-jsk/rtmros_gazebo/pull/135#issuecomment-58844915