Change namespace of DummyClientFace, Signal, Segmenter, SegmentFetcher

refs #3940

Change-Id: Ia3c9b4adcca9ff79a14be705ca9da525914f3dff
diff --git a/src/route/fib.hpp b/src/route/fib.hpp
index e24c61b..1a9b75f 100644
--- a/src/route/fib.hpp
+++ b/src/route/fib.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2022,  The University of Memphis,
+ * Copyright (c) 2014-2023,  The University of Memphis,
  *                           Regents of the University of California,
  *                           Arizona Board of Regents.
  *
@@ -222,7 +222,7 @@
   static inline const ndn::Name MULTICAST_STRATEGY{"/localhost/nfd/strategy/multicast"};
   static inline const ndn::Name BEST_ROUTE_STRATEGY{"/localhost/nfd/strategy/best-route"};
 
-  ndn::util::Signal<Fib, ndn::Name> onPrefixRegistrationSuccess;
+  ndn::signal::Signal<Fib, ndn::Name> onPrefixRegistrationSuccess;
 
 private:
   ndn::Scheduler& m_scheduler;