Adjust includes for the updated locations of ndn-cxx security headers

Change-Id: If598dc04f52875add28b47aa0b2be55f9d7304ec
diff --git a/tests/identity-management-fixture.cpp b/tests/identity-management-fixture.cpp
index e824246..681e076 100644
--- a/tests/identity-management-fixture.cpp
+++ b/tests/identity-management-fixture.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) 2014-2020, Regents of the University of California.
  *
  * This file is part of NDN repo-ng (Next generation of NDN repository).
  * See AUTHORS.md for complete list of repo-ng authors and contributors.
@@ -21,7 +21,7 @@
 #include <ndn-cxx/security/pib/identity.hpp>
 #include <ndn-cxx/security/pib/key.hpp>
 #include <ndn-cxx/security/pib/pib.hpp>
-#include <ndn-cxx/security/v2/certificate.hpp>
+#include <ndn-cxx/security/certificate.hpp>
 #include <ndn-cxx/util/io.hpp>
 #include <boost/filesystem.hpp>
 
@@ -57,7 +57,7 @@
 bool
 IdentityManagementFixture::saveIdentityCertificate(const Name& identity, const std::string& filename, bool wantAdd)
 {
-  ndn::security::v2::Certificate cert;
+  ndn::security::Certificate cert;
   try {
     cert = m_keyChain.getPib().getIdentity(identity).getDefaultKey().getDefaultCertificate();
   }