Reduce namespace nesting (ndn::ndncert -> ndncert)

Change-Id: I5b69a2c3673cccdf07ea0ba3a0e7181894328f47
diff --git a/src/detail/ca-configuration.hpp b/src/detail/ca-configuration.hpp
index ba3de47..2a2a9ff 100644
--- a/src/detail/ca-configuration.hpp
+++ b/src/detail/ca-configuration.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2017-2020, Regents of the University of California.
+/*
+ * Copyright (c) 2017-2021, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -24,7 +24,6 @@
 #include "detail/ca-profile.hpp"
 #include "name-assignment/assignment-func.hpp"
 
-namespace ndn {
 namespace ndncert {
 namespace ca {
 
@@ -67,7 +66,7 @@
   /**
    * @brief Used for CA redirection
    */
-  std::vector<std::shared_ptr<security::Certificate>> redirection;
+  std::vector<std::shared_ptr<Certificate>> redirection;
   /**
    * @brief Name Assignment Functions
    */
@@ -76,6 +75,5 @@
 
 } // namespace ca
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDNCERT_DETAIL_CA_CONFIGURATION_HPP