clean header file include

Change-Id: I5df52db13f964a92bba7cc8659ec6bcc222f5cbb
diff --git a/src/crypto-support/crypto-helper.hpp b/src/crypto-support/crypto-helper.hpp
index 53f57f1..ad8aa22 100644
--- a/src/crypto-support/crypto-helper.hpp
+++ b/src/crypto-support/crypto-helper.hpp
@@ -21,11 +21,10 @@
 #ifndef NDNCERT_CRYPTO_SUPPORT_CRYPTO_HELPER_HPP
 #define NDNCERT_CRYPTO_SUPPORT_CRYPTO_HELPER_HPP
 
+#include "request-state.hpp"
 #include <openssl/ec.h>
 #include <openssl/evp.h>
 
-#include "certificate-request.hpp"
-
 namespace ndn {
 namespace ndncert {