corrected safe_memset() of expired sessions.

src/main-resume.c

@@ -179,10 +179,10 @@ void expire_tls_sessions(main_server_st * s)
 		exp = gnutls_db_check_entry_time(&d);
 
 		if (now - exp > TLS_SESSION_EXPIRATION_TIME) {
-			cache->session_data_size = 0;
 			cache->session_id_size = 0;
 
 			htable_delval(s->tls_db.ht, &iter);
+
 			safe_memset(cache->session_data, 0, cache->session_data_size);
 			talloc_free(cache);
 			s->tls_db.entries--;