Remove multiple logging implementations.

Change-Id: I7474c29b394f37918a35bba58b2fab58a7be930f
diff --git a/aos/ipc_lib/ipc_comparison.cc b/aos/ipc_lib/ipc_comparison.cc
index 1553159..cf5581e 100644
--- a/aos/ipc_lib/ipc_comparison.cc
+++ b/aos/ipc_lib/ipc_comparison.cc
@@ -955,7 +955,7 @@
   ::gflags::ParseCommandLineFlags(&argc, &argv, true);
 
   ::aos::InitNRT();
-  ::aos::logging::AddImplementation(
+  ::aos::logging::SetImplementation(
       new ::aos::logging::StreamLogImplementation(stdout));
 
   return ::aos::Main(argc, argv);