Change #include style

Header files are now always included with their path from the
project's root directory rather than the path relative to
the includer.

Change-Id: If39b8510eef8da00baf5fe88337c45dbdf8c766e
Refs: #3084
diff --git a/tests/unit/security/v2/validator-config/common.hpp b/tests/unit/security/v2/validator-config/common.hpp
index 231e8eb..1083eb5 100644
--- a/tests/unit/security/v2/validator-config/common.hpp
+++ b/tests/unit/security/v2/validator-config/common.hpp
@@ -22,6 +22,8 @@
 #ifndef NDN_TESTS_SECURITY_V2_VALIDATOR_CONFIG_COMMON_HPP
 #define NDN_TESTS_SECURITY_V2_VALIDATOR_CONFIG_COMMON_HPP
 
+#include "ndn-cxx/security/v2/validator-config/common.hpp"
+
 #include <boost/property_tree/info_parser.hpp>
 
 namespace ndn {