security: Rename security/v2/* to security/*

Security v1-v2 transition has been completed for a while and path
separation is no longer needed. However, this commit preserves
`ndn::security::v2` namespace, but makes it inline.

Some commonly used v2 headers are preserved, but are deprecated and
should be avoided in the dependent software.

Change-Id: I26056cb3d34bcdc0a16e06dea8c1a78c03da2d40
diff --git a/tests/unit/security/validator-config.t.cpp b/tests/unit/security/validator-config.t.cpp
index 06e66b0..b4654ac 100644
--- a/tests/unit/security/validator-config.t.cpp
+++ b/tests/unit/security/validator-config.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2018 Regents of the University of California.
+ * Copyright (c) 2013-2020 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -20,13 +20,13 @@
  */
 
 #include "ndn-cxx/security/validator-config.hpp"
+#include "ndn-cxx/security/certificate-fetcher-offline.hpp"
 #include "ndn-cxx/security/command-interest-signer.hpp"
-#include "ndn-cxx/security/v2/certificate-fetcher-offline.hpp"
 #include "ndn-cxx/util/dummy-client-face.hpp"
 
 #include "tests/boost-test.hpp"
 #include "tests/identity-management-fixture.hpp"
-#include "tests/unit/security/v2/validator-config/common.hpp"
+#include "tests/unit/security/validator-config/common.hpp"
 
 namespace ndn {
 namespace security {