Migrate to ndn-cxx 0.7.1: Part 1

Change-Id: I621a6230272cfde5d84aa5ca9abdf40a91337491
diff --git a/src/identity-challenge/challenge-credential.hpp b/src/identity-challenge/challenge-credential.hpp
index 2c0229b..49670f6 100644
--- a/src/identity-challenge/challenge-credential.hpp
+++ b/src/identity-challenge/challenge-credential.hpp
@@ -76,7 +76,7 @@
   parseConfigFile();
 
 PUBLIC_WITH_TESTS_ELSE_PRIVATE:
-  std::list<security::v2::Certificate> m_trustAnchors;
+  std::list<security::Certificate> m_trustAnchors;
   std::string m_configFile;
 };