gluon-ebtables-source-filter: use new gluon.site library to avoid 'or {}' syntax

package/gluon-ebtables-source-filter/files/lib/gluon/ebtables/110-local-forward-allow-ipv6

-site = require('gluon.site_config')
+site = require('gluon.site')
 
 rule('LOCAL_FORWARD -p IPv6 --ip6-src fe80::/64 -j RETURN')
 rule('LOCAL_FORWARD -p IPv6 --ip6-src ::/128 --ip6-proto ipv6-icmp -j RETURN')
-rule('LOCAL_FORWARD -p IPv6 --ip6-src ' .. site.prefix6 .. ' -j RETURN')
+rule('LOCAL_FORWARD -p IPv6 --ip6-src ' .. site.prefix6() .. ' -j RETURN')
 
-for _, prefix in ipairs(site.extra_prefixes6 or {}) do
+for _, prefix in ipairs(site.extra_prefixes6({})) do
 	rule('LOCAL_FORWARD -p IPv6 --ip6-src ' .. prefix .. ' -j RETURN')
 end