Remove unused Cleanup() call

It was used to clean up shared memory.  We don't construct that anymore,
so remove the useless call.

Change-Id: I8087cef2afce184f66721a9995a63053fb278ec7
diff --git a/y2020/setpoint_setter.cc b/y2020/setpoint_setter.cc
index 1cbc518..f4aa03a 100644
--- a/y2020/setpoint_setter.cc
+++ b/y2020/setpoint_setter.cc
@@ -30,5 +30,5 @@
   setpoint_builder.add_hood(FLAGS_hood);
   builder.Send(setpoint_builder.Finish());
 
-  aos::Cleanup();
+  return 0;
 }