Faces split: Don't leave CD_NORMAL after split

This is supposed to be a temporary layer.

If someone needs loop normals after split it should explicitly
ask for that.

intern/cycles/blender/blender_util.h

@@ -80,6 +80,7 @@ static inline BL::Mesh object_to_mesh(BL::BlendData& data,
 			}
 			else {
 				me.split_faces();
+				me.calc_normals_split();
 			}
 		}
 		if(subdivision_type == Mesh::SUBDIVISION_NONE) {