Follow namespace change of DummyClientFace, Signal, SegmentFetcher

Change-Id: Icb0d0be2fe6165149fb46c9e6e7b13eed6650a0c
diff --git a/tests/unit/read-handle.t.cpp b/tests/unit/read-handle.t.cpp
index a6bfed5..9d36b18 100644
--- a/tests/unit/read-handle.t.cpp
+++ b/tests/unit/read-handle.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2022,  Regents of the University of California.
+ * Copyright (c) 2014-2023,  Regents of the University of California.
  *
  * This file is part of NDN repo-ng (Next generation of NDN repository).
  * See AUTHORS.md for complete list of repo-ng authors and contributors.
@@ -66,7 +66,7 @@
   }
 
 public:
-  ndn::util::DummyClientFace face;
+  ndn::DummyClientFace face;
   ndn::KeyChain keyChain;
   ndn::Scheduler scheduler;