mgmt: simplify StatusDataset implementation

Change-Id: Icf21cfd8bc47333461dadd06c347b723e77f5784
diff --git a/tests/unit/mgmt/nfd/controller-fixture.hpp b/tests/unit/mgmt/nfd/controller-fixture.hpp
index 8afee13..38b44fd 100644
--- a/tests/unit/mgmt/nfd/controller-fixture.hpp
+++ b/tests/unit/mgmt/nfd/controller-fixture.hpp
@@ -62,8 +62,8 @@
   ndn::util::DummyClientFace face;
   DummyValidator m_validator;
   Controller controller;
-  Controller::CommandFailureCallback commandFailCallback;
-  Controller::DatasetFailureCallback datasetFailCallback;
+  CommandFailureCallback commandFailCallback;
+  DatasetFailureCallback datasetFailCallback;
   std::vector<uint32_t> failCodes;
 };