Debian 8. В файле /etc/systemd/system/multi-user.target.wants/openvpn.service написано вот такое
[Unit]
Description=OpenVPN service
After=network.target
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/true
ExecReload=/bin/true
WorkingDirectory=/etc/openvpn
[Install]
WantedBy=multi-user.target