Fix crash when you change the curve resolution in Edit Mode of the Blender Render engine

Same problem as previous commit, but now in `drawobject.c`.
Also added a comment to the equivalent line in `draw_cache_imp_curve.c`.

source/blender/draw/intern/draw_cache_impl_curve.c

@@ -126,6 +126,7 @@ static int curve_render_normal_len_get(const ListBase *lb, const CurveCache *ob_
 			nr -= skip;
 		}
 #else
+		/* Same as loop above */
 		normal_len += (nr / (skip + 1)) + ((nr % (skip + 1)) != 0);
 #endif
 	}

source/blender/editors/space_view3d/drawobject.c

@@ -7405,7 +7405,7 @@ static void draw_editnurb(
 			}
 #else
 			/* Same as loop above */
-			count += 4 * max_ii((nr + max_ii(skip - 1, 0)) / (skip + 1), 0);
+			count += (nr / (skip + 1)) + ((nr % (skip + 1)) != 0);
 #endif
 		}