const correctness fixes for OpenSSL 4

Index: tls_conninfo.c
--- tls_conninfo.c.orig
+++ tls_conninfo.c
@@ -72,7 +72,7 @@ tls_get_peer_cert_hash(struct tls *ctx, char **hash)
 static int
 tls_get_peer_cert_issuer(struct tls *ctx,  char **issuer)
 {
-	X509_NAME *name = NULL;
+	const X509_NAME *name = NULL;
 
 	*issuer = NULL;
 	if (ctx->ssl_peer_cert == NULL)
@@ -88,7 +88,7 @@ tls_get_peer_cert_issuer(struct tls *ctx,  char **issu
 static int
 tls_get_peer_cert_subject(struct tls *ctx, char **subject)
 {
-	X509_NAME *name = NULL;
+	const X509_NAME *name = NULL;
 
 	*subject = NULL;
 	if (ctx->ssl_peer_cert == NULL)
