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/tpm/back-end-wrapper-file.hpp b/tests/unit/security/tpm/back-end-wrapper-file.hpp
index dabd6d3..89c58d0 100644
--- a/tests/unit/security/tpm/back-end-wrapper-file.hpp
+++ b/tests/unit/security/tpm/back-end-wrapper-file.hpp
@@ -22,7 +22,8 @@
 #ifndef NDN_TESTS_SECURITY_TPM_BACK_END_WRAPPER_FILE_HPP
 #define NDN_TESTS_SECURITY_TPM_BACK_END_WRAPPER_FILE_HPP
 
-#include "security/tpm/back-end-file.hpp"
+#include "ndn-cxx/security/tpm/back-end-file.hpp"
+
 #include <boost/filesystem.hpp>
 
 namespace ndn {