Update the NDNCERT library to version NDNCERT v2

spec:[https://github.com/named-data/ndncert/wiki/NDNCERT-Protocol-new]

Change-Id: Ia480a8e70c4b38ca170dfe2fcf50d1265ab65f46
diff --git a/tests/database-fixture.hpp b/tests/database-fixture.hpp
index fc9da55..ffe00b0 100644
--- a/tests/database-fixture.hpp
+++ b/tests/database-fixture.hpp
@@ -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) 2014-2019, Regents of the University of California,
  *                          Arizona Board of Regents,
  *                          Colorado State University,
  *                          University Pierre & Marie Curie, Sorbonne University,
@@ -36,7 +36,7 @@
 namespace ndncert {
 namespace tests {
 
-class DatabaseFixture : public IdentityManagementV2TimeFixture
+class DatabaseFixture : public IdentityManagementTimeFixture
 {
 public:
   DatabaseFixture()