[clang-tidy] remove needless std::move

Found with performance-move-const-arg

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/client/ThreadBackgroundCommand.cxx

@@ -54,7 +54,7 @@ ThreadBackgroundCommand::DeferredFinish() noexcept
 	Response response(client, 0);
 
 	if (error) {
-		PrintError(response, std::move(error));
+		PrintError(response, error);
 	} else {
 		SendResponse(response);
 		command_success(client);