security: consistently use EVP_MD conversion helper

Change-Id: Icd95009fba223c461988fe7b341be55972d30f91
diff --git a/src/security/detail/openssl-helper.hpp b/src/security/detail/openssl-helper.hpp
index dfc630d..51a4a36 100644
--- a/src/security/detail/openssl-helper.hpp
+++ b/src/security/detail/openssl-helper.hpp
@@ -30,7 +30,7 @@
 namespace detail {
 
 const EVP_MD*
-toDigestEvpMd(DigestAlgorithm algo);
+digestAlgorithmToEvpMd(DigestAlgorithm algo);
 
 int
 getEvpPkeyType(EVP_PKEY* key);