Remove multiple logging implementations.

Change-Id: I7474c29b394f37918a35bba58b2fab58a7be930f
diff --git a/aos/vision/tools/camera_primer.cc b/aos/vision/tools/camera_primer.cc
index 1ac96fd..e1d5fc5 100644
--- a/aos/vision/tools/camera_primer.cc
+++ b/aos/vision/tools/camera_primer.cc
@@ -27,7 +27,7 @@
 // target_sender
 int main(int argc, char **argv) {
   ::aos::logging::Init();
-  ::aos::logging::AddImplementation(
+  ::aos::logging::SetImplementation(
       new ::aos::logging::StreamLogImplementation(stdout));
 
   aos::vision::CameraParams params;