security: adjust description of PibImpl interfaces

1. Intialize default setting when there is no default setting
2. Removal method should be deep removal.

Change-Id: Id30947834a8002b6dc177ac18c6beae2600efa92
Refs: #2896, #2898
diff --git a/tests/unit-tests/security/key.t.cpp b/tests/unit-tests/security/key.t.cpp
index 3d3c4e3..27db02c 100644
--- a/tests/unit-tests/security/key.t.cpp
+++ b/tests/unit-tests/security/key.t.cpp
@@ -21,7 +21,7 @@
 
 #include "security/key.hpp"
 #include "security/pib.hpp"
-#include "security/in-memory-pib-impl.hpp"
+#include "security/pib-memory.hpp"
 #include "pib-data-fixture.hpp"
 
 #include "boost-test.hpp"
@@ -45,7 +45,7 @@
   else
     BOOST_CHECK(true);
 
-  auto pibImpl = make_shared<InMemoryPibImpl>();
+  auto pibImpl = make_shared<PibMemory>();
   key = Key(id1, id1Key1Name.get(-1), id1Key1, pibImpl);
 
   BOOST_CHECK_EQUAL(static_cast<bool>(key), true);
@@ -59,7 +59,7 @@
 
 BOOST_FIXTURE_TEST_CASE(TestCertificateOperation, PibDataFixture)
 {
-  auto pibImpl = make_shared<InMemoryPibImpl>();
+  auto pibImpl = make_shared<PibMemory>();
 
   Key key11(id1, id1Key1Name.get(-1), id1Key1, pibImpl);