Reflection image generated by directional light

To test the behavior of Unity 5 lighting,
I've generated a simple scene with all sky box effect turned off. A single direction light shining
downward to a reflective surface.

The lighting is good as expected , and in addition, there is a reflection image of the light
source shown on the floor when the FPS character look down. This reflection image
is very good when the directional light represent the sun. But for other purpose,
I found no way to alter the properties or turn off this reflection. could I turn this
reflection off or make it other shape/color/size ?

My testing project and a captured image is as attached.