examples: minor code cleanups

Change-Id: I928da00f996da4d8bc1b93b37f2a3fdc236a9d11
diff --git a/src/common.hpp b/src/common.hpp
index 24df62f..4232aa0 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -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
  *
  * NAC library is free software: you can redistribute it and/or modify it under the
  * terms of the GNU Lesser General Public License as published by the Free Software
@@ -51,7 +51,6 @@
 #include <ndn-cxx/security/validator.hpp>
 
 #include <boost/assert.hpp>
-#include <boost/core/noncopyable.hpp>
 
 namespace ndn::nac {