tests: Implement IdentityManagementV2Fixture for v2::KeyChain

The old IdentityManagementFixture is renamed to IdentityManagementV1Fixture.

This commit also removes global KeyChainFixture, as it doesn't work with
TestKeyChain test suites.  Instead, IdentityManagementFixtures are
customizing PIB/TPM modules.

Change-Id: Iadc43b78523cd43bff4f454d6aea2fca8107a650
Refs: #2926
diff --git a/tests/unit-tests/security/command-interest-validator.t.cpp b/tests/unit-tests/security/command-interest-validator.t.cpp
index f31f3a3..09ae2b9 100644
--- a/tests/unit-tests/security/command-interest-validator.t.cpp
+++ b/tests/unit-tests/security/command-interest-validator.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2013-2016 Regents of the University of California.
+ * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -56,7 +56,7 @@
   {
     Name name("/localhost/CommandInterestValidatorIdentity");
     name.appendSequenceNumber(identity);
-    BOOST_REQUIRE(m_keyChain.doesIdentityExist(name) || this->addIdentity(name));
+    this->addIdentity(name);
     return name;
   }