tests: avoid deprecated boost headers

Change-Id: Ifac2a9e69bb7dd679e3540dd0911a15cea90af30
diff --git a/tests/unit/daemon/rrset.cpp b/tests/unit/daemon/rrset.cpp
index d202e78..f9e2704 100644
--- a/tests/unit/daemon/rrset.cpp
+++ b/tests/unit/daemon/rrset.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2018, Regents of the University of California.
+ * Copyright (c) 2014-2020, Regents of the University of California.
  *
  * This file is part of NDNS (Named Data Networking Domain Name Service).
  * See AUTHORS.md for complete list of NDNS authors and contributors.
@@ -21,6 +21,12 @@
 
 #include "test-common.hpp"
 
+#if BOOST_VERSION >= 105900
+#include <boost/test/tools/output_test_stream.hpp>
+#else
+#include <boost/test/output_test_stream.hpp>
+#endif
+
 namespace ndn {
 namespace ndns {
 namespace tests {