update include under detail

Change-Id: Ic2dbb76f7c8b3de9ba499a76efa95e400300cdb6
diff --git a/src/detail/error-encoder.hpp b/src/detail/error-encoder.hpp
index 76ecb36..e8cdf82 100644
--- a/src/detail/error-encoder.hpp
+++ b/src/detail/error-encoder.hpp
@@ -21,7 +21,7 @@
 #ifndef NDNCERT_PROTOCOL_DETAIL_ERROR_ENCODER_HPP
 #define NDNCERT_PROTOCOL_DETAIL_ERROR_ENCODER_HPP
 
-#include "../configuration.hpp"
+#include "configuration.hpp"
 
 namespace ndn {
 namespace ndncert {