message: Remove LOG(ERROR) when executor fails to create a kernel
  This can happen under normal circumstances, e.g. a shape refiner
  trying to create an executor, and does not always constitute an error.
diff: @@ -658,7 +658,6 @@ Status ExecutorImpl::Initialize(const Graph& graph) {
  if (!s.ok()) {
  item->kernel = nullptr;
  s = AttachDef(s, *n);
  - LOG(ERROR) << "Executor failed to create kernel. " << s;
  return s;
  }
  CHECK(item->kernel);
  