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/test-home-env-saver.hpp b/tests/unit/test-home-env-saver.hpp
index dc3d956..732c2d8 100644
--- a/tests/unit/test-home-env-saver.hpp
+++ b/tests/unit/test-home-env-saver.hpp
@@ -19,11 +19,11 @@
  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
  */
 
-#ifndef NDN_TESTS_UNIT_TESTS_TEST_HOME_ENV_SAVER_HPP
-#define NDN_TESTS_UNIT_TESTS_TEST_HOME_ENV_SAVER_HPP
+#ifndef NDN_TESTS_UNIT_TEST_HOME_ENV_SAVER_HPP
+#define NDN_TESTS_UNIT_TEST_HOME_ENV_SAVER_HPP
 
-#include <string>
 #include <cstdlib>
+#include <string>
 
 namespace ndn {
 namespace tests {
@@ -41,7 +41,7 @@
   ~TestHomeEnvSaver()
   {
     if (!m_HOME.empty())
-      setenv("TEST_HOME", m_HOME.c_str(), 1);
+      setenv("TEST_HOME", m_HOME.data(), 1);
     else
       unsetenv("TEST_HOME");
   }
@@ -53,4 +53,4 @@
 } // namespace tests
 } // namespace ndn
 
-#endif // NDN_TESTS_UNIT_TESTS_TEST_HOME_ENV_SAVER_HPP
+#endif // NDN_TESTS_UNIT_TEST_HOME_ENV_SAVER_HPP