**breaking change**: Switch Face and related classes to v2::KeyChain

security::v2::KeyChain is now exposed as ndn::KeyChain, which should
ensure that dependent code can be mostly compiled.  However, expect code
that explicitly uses the old KeyChain interface to be broken.

Change-Id: I7330d0250d92f3f0f2570ab6d0214ab3dfdd18cc
Refs: #3098
diff --git a/src/mgmt/dispatcher.hpp b/src/mgmt/dispatcher.hpp
index a8b30b4..b3c9967 100644
--- a/src/mgmt/dispatcher.hpp
+++ b/src/mgmt/dispatcher.hpp
@@ -145,7 +145,7 @@
    *  \param signingInfo signing parameters to sign Data with \p keyChain
    *  \param imsCapacity capacity of the internal InMemoryStorage used by dispatcher
    */
-  Dispatcher(Face& face, security::v1::KeyChain& keyChain,
+  Dispatcher(Face& face, KeyChain& keyChain,
              const security::SigningInfo& signingInfo = security::SigningInfo(),
              size_t imsCapacity = 256);
 
@@ -462,7 +462,7 @@
   std::unordered_map<Name, TopPrefixEntry> m_topLevelPrefixes;
 
   Face& m_face;
-  security::v1::KeyChain& m_keyChain;
+  KeyChain& m_keyChain;
   security::SigningInfo m_signingInfo;
 
   typedef std::unordered_map<PartialName, InterestHandler> HandlerMap;