table: code modernization

Change-Id: I9ca9a1905aea316726d0323f4537a2420890735f
diff --git a/daemon/table/network-region-table.cpp b/daemon/table/network-region-table.cpp
index 828a35b..c7e9cea 100644
--- a/daemon/table/network-region-table.cpp
+++ b/daemon/table/network-region-table.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2017,  Regents of the University of California,
+ * Copyright (c) 2014-2019,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -24,7 +24,6 @@
  */
 
 #include "network-region-table.hpp"
-#include <boost/range/adaptor/map.hpp>
 
 namespace nfd {