Drop unnecessary v2 namespace qualifications

Change-Id: I6358bac6860ca8f2e9cdbd00bb2a929e3af5b2da
diff --git a/tools/ndnsec/unlock-tpm.cpp b/tools/ndnsec/unlock-tpm.cpp
index d79db7f..bcf7ca0 100644
--- a/tools/ndnsec/unlock-tpm.cpp
+++ b/tools/ndnsec/unlock-tpm.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2019 Regents of the University of California.
+ * Copyright (c) 2013-2021 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -61,7 +61,7 @@
   }
 
 #ifdef NDN_CXX_HAVE_GETPASS
-  security::v2::KeyChain keyChain;
+  KeyChain keyChain;
 
   char* password = ::getpass("Password to unlock the TPM: ");
   if (password == nullptr) {