core: reimplement logging using ndn-cxx's facility

Change-Id: Ifc7c5d70a61ad405dc1f1adfa522a2c0ad1586ab
Refs: #4580
diff --git a/tests/test-common.hpp b/tests/test-common.hpp
index b365f9b..110a1e2 100644
--- a/tests/test-common.hpp
+++ b/tests/test-common.hpp
@@ -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) 2014-2018,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -29,7 +29,6 @@
 #include "boost-test.hpp"
 
 #include "core/global-io.hpp"
-#include "core/logger.hpp"
 
 #include <ndn-cxx/util/time-unit-test-clock.hpp>