Fixing missing assignment in Convex class (#222)

Author: k-okada

include/fcl/shape/geometric_shapes.h

@@ -277,6 +277,7 @@ class Convex : public ShapeBase
     plane_dis = plane_dis_;
     num_planes = num_planes_;
     points = points_;
+    num_points = num_points_;
     polygons = polygons_;
     edges = NULL;