Have the few apps that accessed EVP_MD directly use accessors instead

Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/apps/speed.c b/apps/speed.c
index c90729c..1434a95 100644
--- a/apps/speed.c
+++ b/apps/speed.c
@@ -1687,7 +1687,7 @@
                 EVP_CIPHER_CTX_cleanup(&ctx);
             }
             if (evp_md) {
-                names[D_EVP] = OBJ_nid2ln(evp_md->type);
+                names[D_EVP] = OBJ_nid2ln(EVP_MD_type(evp_md));
                 print_message(names[D_EVP], save_count, lengths[j]);
 
                 Time_F(START);