Fix tlsauth_keydir save on vpn_openvpn_server.php. Fixes #9030
(cherry picked from commit 7dca65a19d08393cdb36f22fe98b847b46d9caf9)
Fix tlsauth_keydir save on vpn_openvpn_server.php. Fixes #9030
(cherry picked from commit 7dca65a19d08393cdb36f22fe98b847b46d9caf9)