security: Make addKey/Cert behavior of PibImpl consistent

Change-Id: I30c6dd0007e9095ee07f7a8eda3b20db4c34c513
Refs: #3351
diff --git a/tests/unit-tests/security/pib/pib-data-fixture.hpp b/tests/unit-tests/security/pib/pib-data-fixture.hpp
index 82a8f3e..aad5916 100644
--- a/tests/unit-tests/security/pib/pib-data-fixture.hpp
+++ b/tests/unit-tests/security/pib/pib-data-fixture.hpp
@@ -36,6 +36,15 @@
   PibDataFixture();
 
 public:
+  v2::Certificate id1Key1Cert1;
+  v2::Certificate id1Key1Cert2;
+  v2::Certificate id1Key2Cert1;
+  v2::Certificate id1Key2Cert2;
+  v2::Certificate id2Key1Cert1;
+  v2::Certificate id2Key1Cert2;
+  v2::Certificate id2Key2Cert1;
+  v2::Certificate id2Key2Cert2;
+
   Name id1;
   Name id2;
 
@@ -48,15 +57,6 @@
   Buffer id1Key2;
   Buffer id2Key1;
   Buffer id2Key2;
-
-  v2::Certificate id1Key1Cert1;
-  v2::Certificate id1Key1Cert2;
-  v2::Certificate id1Key2Cert1;
-  v2::Certificate id1Key2Cert2;
-  v2::Certificate id2Key1Cert1;
-  v2::Certificate id2Key1Cert2;
-  v2::Certificate id2Key2Cert1;
-  v2::Certificate id2Key2Cert2;
 };
 
 } // namespace tests