Actually manage memory in the old-style AOS logging

LeakSanitizer should be happy with it now. It's also still just as
thread-safe.

Change-Id: Id09a0349657cf4f719267b053f0ea3d8ec366256
diff --git a/y2019/vision/global_calibration.cc b/y2019/vision/global_calibration.cc
index 52a6e52..af2ad54 100644
--- a/y2019/vision/global_calibration.cc
+++ b/y2019/vision/global_calibration.cc
@@ -104,7 +104,7 @@
 
   ::aos::logging::Init();
   ::aos::logging::SetImplementation(
-      new ::aos::logging::StreamLogImplementation(stderr));
+      std::make_shared<::aos::logging::StreamLogImplementation>(stderr));
 
   TargetFinder target_finder;