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/v1/key-chain.t.cpp b/tests/unit-tests/security/v1/key-chain.t.cpp
index 6130cae..36dac9c 100644
--- a/tests/unit-tests/security/v1/key-chain.t.cpp
+++ b/tests/unit-tests/security/v1/key-chain.t.cpp
@@ -26,7 +26,7 @@
 #include "boost-test.hpp"
 #include "dummy-keychain.hpp"
 #include "../../test-home-env-saver.hpp"
-#include "key-chain-fixture.hpp"
+#include "test-home-fixture.hpp"
 #include "identity-management-fixture.hpp"
 
 #include <boost/algorithm/string.hpp>