createlinks: execute nethserver-openvpn-delserver and expand /etc/openvpn/host-to-net.conf on nethserver-vpn-save event. Refs #1958
nethserver-openvpn-genclient: add log append option. Refs #1958
nethserver-openvpn-delclient: fix parameter handling. Refs #1958
nethserver-openvpn-bridge: add device prop to green interface to avoid warnings. Refs #1956