security: consistently use EVP_MD conversion helper

Change-Id: Icd95009fba223c461988fe7b341be55972d30f91
diff --git a/src/security/transform/hmac-filter.cpp b/src/security/transform/hmac-filter.cpp
index d45cd85..e150a79 100644
--- a/src/security/transform/hmac-filter.cpp
+++ b/src/security/transform/hmac-filter.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2013-2016 Regents of the University of California.
+/*
+ * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -74,7 +74,7 @@
   BOOST_ASSERT(key != nullptr);
   BOOST_ASSERT(keyLen > 0);
 
-  const EVP_MD* algorithm = detail::toDigestEvpMd(algo);
+  const EVP_MD* algorithm = detail::digestAlgorithmToEvpMd(algo);
   if (algorithm == nullptr)
     BOOST_THROW_EXCEPTION(Error(getIndex(), "Unsupported digest algorithm"));