security: consistently use EVP_MD conversion helper

Change-Id: Icd95009fba223c461988fe7b341be55972d30f91
diff --git a/src/security/detail/openssl-helper.cpp b/src/security/detail/openssl-helper.cpp
index 27177e2..d854776 100644
--- a/src/security/detail/openssl-helper.cpp
+++ b/src/security/detail/openssl-helper.cpp
@@ -26,7 +26,7 @@
 namespace detail {
 
 const EVP_MD*
-toDigestEvpMd(DigestAlgorithm algo)
+digestAlgorithmToEvpMd(DigestAlgorithm algo)
 {
   switch (algo) {
   case DigestAlgorithm::SHA256: