build: Warnings correction for gcc 4.2

Also in this commit some code style corrections.

Change-Id: Idf2b5b96b328fb3dbea7440362c84d7759a10ec5
Refs: #1429
diff --git a/tests/security/test-encode-decode-certificate.cpp b/tests/security/test-encode-decode-certificate.cpp
index 05c310c..b9d8d36 100644
--- a/tests/security/test-encode-decode-certificate.cpp
+++ b/tests/security/test-encode-decode-certificate.cpp
@@ -3,15 +3,12 @@
  * See COPYING for copyright and distribution information.
  */
 
-#include <boost/test/unit_test.hpp>
-
 #include "security/certificate.hpp"
 #include "security/public-key.hpp"
 
 #include "security/cryptopp.hpp"
 
-#include <fstream>
-#include <boost/test/output_test_stream.hpp>
+#include "boost-test.hpp"
 
 using namespace std;
 namespace ndn {