This is right of the box on a new ROS Indigo install under Ubuntu 14.04.  To reproduce run:
$ roscore
$ roslaunch turtlebot_gazebo turtlebot_world.launch
$ roslaunch turtlebot_gazebo amcl_demo.launch
$ roslaunch turtlebot_rviz_launchers view_navigation.launch
Now set a 2D Nav Goal in RViz and robot executes a spiral path toward goal.