Adapt to ndn-cxx security changes

refs: #4090, #4195, #3828

Change-Id: Ie1bf11d604af12d3b26fba24054ed67fe735ae7c
diff --git a/src/socket.cpp b/src/socket.cpp
index 4a947d7..0fd5707 100644
--- a/src/socket.cpp
+++ b/src/socket.cpp
@@ -129,7 +129,7 @@
   if (m_signingId.empty())
     m_keyChain.sign(*data);
   else
-    m_keyChain.signByIdentity(*data, m_signingId);
+    m_keyChain.sign(*data, security::signingByIdentity(m_signingId));
 
   m_ims.insert(*data);
 
@@ -152,7 +152,7 @@
   if (m_signingId.empty())
     m_keyChain.sign(*data);
   else
-    m_keyChain.signByIdentity(*data, m_signingId);
+    m_keyChain.sign(*data, security::signingByIdentity(m_signingId));
 
   m_ims.insert(*data);