SSL_clear_mode exists; we can use it.

src/common/tortls.c

@@ -2239,8 +2239,7 @@ tor_tls_finish_handshake(tor_tls_t *tls)
   if (tls->isServer) {
     SSL_set_info_callback(tls->ssl, NULL);
     SSL_set_verify(tls->ssl, SSL_VERIFY_PEER, always_accept_verify_cb);
-    /* There doesn't seem to be a clear OpenSSL API to clear mode flags. */
-    tls->ssl->mode &= ~SSL_MODE_NO_AUTO_CHAIN;
+    SSL_clear_mode(tls->ssl, SSL_MODE_NO_AUTO_CHAIN);
 #ifdef V2_HANDSHAKE_SERVER
     if (tor_tls_client_is_using_v2_ciphers(tls->ssl)) {
       /* This check is redundant, but back when we did it in the callback,