Ensure all include guards start with "NDN_CXX_"

Change-Id: I530e862ef391db8a2f2d3aa6df0fd0e2f64ae5b6
diff --git a/tools/ndnsec/util.hpp b/tools/ndnsec/util.hpp
index f069c34..8aed837 100644
--- a/tools/ndnsec/util.hpp
+++ b/tools/ndnsec/util.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2020 Regents of the University of California.
+ * Copyright (c) 2013-2021 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -19,8 +19,8 @@
  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
  */
 
-#ifndef NDN_TOOLS_NDNSEC_UTIL_HPP
-#define NDN_TOOLS_NDNSEC_UTIL_HPP
+#ifndef NDN_CXX_TOOLS_NDNSEC_UTIL_HPP
+#define NDN_CXX_TOOLS_NDNSEC_UTIL_HPP
 
 #include "ndn-cxx/security/key-chain.hpp"
 
@@ -67,4 +67,4 @@
 } // namespace ndnsec
 } // namespace ndn
 
-#endif // NDN_TOOLS_NDNSEC_UTIL_HPP
+#endif // NDN_CXX_TOOLS_NDNSEC_UTIL_HPP