Fix Smac cleanup (#2477)

* fix smac2d cleanup

* same for hybrid

Author: doisyg

nav2_smac_planner/src/smac_planner_2d.cpp

@@ -184,8 +184,10 @@ void SmacPlanner2D::cleanup()
     _name.c_str());
   _a_star.reset();
   _smoother.reset();
-  _costmap_downsampler->on_cleanup();
-  _costmap_downsampler.reset();
+  if (_costmap_downsampler) {
+    _costmap_downsampler->on_cleanup();
+    _costmap_downsampler.reset();
+  }
   _raw_plan_publisher.reset();
 }
 

nav2_smac_planner/src/smac_planner_hybrid.cpp

@@ -221,8 +221,10 @@ void SmacPlannerHybrid::cleanup()
     _name.c_str());
   _a_star.reset();
   _smoother.reset();
-  _costmap_downsampler->on_cleanup();
-  _costmap_downsampler.reset();
+  if (_costmap_downsampler) {
+    _costmap_downsampler->on_cleanup();
+    _costmap_downsampler.reset();
+  }
   _raw_plan_publisher.reset();
 }