encoding: remove duplicate buf() and get() methods from Buffer class

Change-Id: If885d4199d6c9df9b9b46664c3641c9a14a77eab
diff --git a/tests/unit-tests/security/pib/identity.t.cpp b/tests/unit-tests/security/pib/identity.t.cpp
index 239da12..6f631e5 100644
--- a/tests/unit-tests/security/pib/identity.t.cpp
+++ b/tests/unit-tests/security/pib/identity.t.cpp
@@ -82,12 +82,12 @@
   BOOST_CHECK_NE(identity1, Identity());
   BOOST_CHECK_EQUAL(Identity(), Identity());
 
-  identity1.addKey(id1Key1.buf(), id1Key1.size(), id1Key1Name);
+  identity1.addKey(id1Key1.data(), id1Key1.size(), id1Key1Name);
   BOOST_CHECK_NO_THROW(identity2.getKey(id1Key1Name));
   identity2.removeKey(id1Key1Name);
   BOOST_CHECK_THROW(identity1.getKey(id1Key1Name), Pib::Error);
 
-  identity1.setDefaultKey(id1Key1.buf(), id1Key1.size(), id1Key1Name);
+  identity1.setDefaultKey(id1Key1.data(), id1Key1.size(), id1Key1Name);
   BOOST_CHECK_NO_THROW(identity2.getDefaultKey());
 }