reforis-openvpn-plugin: change Install section
Currently, in this package was included just CSV file for redirect without any other files, which leads that ReForis OpenVPN does not show. Because generic Install section for ReForis plugin was overwritten by this Makefile.
Fixes: c97fc2d6 ("reforis-openvpn-plugin: bundle foris redirect") and https://gitlab.nic.cz/turris/turris-os-packages/-/merge_requests/386
Package is compile tested for Turris Omnia, HBL branch. Contents of the package was verified.