c/util: Making util/crypto.h a public header

Change-Id: Ie63d3b5b206ae7e027e11077b6c0a039ed75eb92
diff --git a/src/util/ndnd-id-fetcher.hpp b/src/util/ndnd-id-fetcher.hpp
index 4f5758d..843eb83 100644
--- a/src/util/ndnd-id-fetcher.hpp
+++ b/src/util/ndnd-id-fetcher.hpp
@@ -9,7 +9,7 @@
 #define NDN_NDND_ID_FETCHER_HPP
 
 #include <ndn-cpp/common.hpp>
-#include "../c/util/crypto.h"
+#include "ndn-cpp/c/util/crypto.h"
 
 namespace ndn {