security: Adapt PIB to NDN Certificate Format version 2.0

The certificate format can be found at docs/specs/certificate-format.rst

Change-Id: I5656837f09ce327e06a0cb1abdf16ac28fe0b823
Refs: #3202
diff --git a/src/security/pib/certificate-container.cpp b/src/security/pib/certificate-container.cpp
index a05dd52..fa8d058 100644
--- a/src/security/pib/certificate-container.cpp
+++ b/src/security/pib/certificate-container.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).
  *
@@ -24,6 +24,7 @@
 
 namespace ndn {
 namespace security {
+namespace pib {
 
 CertificateContainer::const_iterator::const_iterator(std::set<Name>::const_iterator it,
                                                      shared_ptr<PibImpl> impl)
@@ -32,7 +33,7 @@
 {
 }
 
-v1::IdentityCertificate
+v2::Certificate
 CertificateContainer::const_iterator::operator*()
 {
   return m_impl->getCertificate(*m_it);
@@ -100,5 +101,6 @@
   return m_certNames.size();
 }
 
+} // namespace pib
 } // namespace security
 } // namespace ndn