ipsec: T2816: fix NameError
ipsec: T2816: fix NameError

Commit a5cd877a0a ("ipsec: T2816: Migrate ipsec-settings.xml.in and charon.conf
to vpn_ipsec.py") unfortunately removed the dictionary definition for "data"
which is required when running the l2tp handler script.

vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x