MeshLambertMaterial warning fixed for teapot demo

MeshLambertMaterial does not have shading properties thus leading to a warning in the console.

examples/webgl_geometry_teapot.html

@@ -134,7 +134,7 @@
 
 				flatMaterial = new THREE.MeshPhongMaterial( { color: materialColor, specular: 0x0, shading: THREE.FlatShading, side: THREE.DoubleSide } );
 
-				gouraudMaterial = new THREE.MeshLambertMaterial( { color: materialColor, shading: THREE.SmoothShading, side: THREE.DoubleSide } );
+				gouraudMaterial = new THREE.MeshLambertMaterial( { color: materialColor, side: THREE.DoubleSide } );
 
 				phongMaterial = new THREE.MeshPhongMaterial( { color: materialColor, shading: THREE.SmoothShading, side: THREE.DoubleSide } );