* Change KEY/HMAC_KEY to __CHANGEME__, which is rejected by fwknopd
during start-up. The value CHANGEME is used only by LuCI package
luci-app-fwknopd - pull request for generating keys directly from
LuCI has been created already.
* Add sensible defaults for ENABLE_IPT_FORWARDING and ENABLE_NAT_DNS,
which both are/were set by luci-app-fwknopd. Move the defaults here.
Signed-off-by: Oldřich Jedlička <oldium.pro@gmail.com>