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

Change-Id: Ie63d3b5b206ae7e027e11077b6c0a039ed75eb92
diff --git a/tests/test-encode-decode-benchmark.cpp b/tests/test-encode-decode-benchmark.cpp
index ad2c40a..f68502d 100644
--- a/tests/test-encode-decode-benchmark.cpp
+++ b/tests/test-encode-decode-benchmark.cpp
@@ -20,7 +20,7 @@
 #include "../src/c/encoding/binary-xml-decoder.h"
 #include "../src/c/data.h"
 #include "../src/c/encoding/binary-xml-data.h"
-#include "../src/c/util/crypto.h"
+#include <ndn-cpp/c/util/crypto.h>
 
 using namespace std;
 using namespace ndn;