don't update costs if inflation radius is zero

costmap_2d/plugins/inflation_layer.cpp

@@ -172,7 +172,7 @@ void InflationLayer::onFootprintChanged()
 void InflationLayer::updateCosts(costmap_2d::Costmap2D& master_grid, int min_i, int min_j, int max_i, int max_j)
 {
   boost::unique_lock < boost::recursive_mutex > lock(*inflation_access_);
-  if (!enabled_)
+  if (!enabled_ || (cell_inflation_radius_ == 0))
     return;
 
   // make sure the inflation list is empty at the beginning of the cycle (should always be true)