wrap fixup code in do-block

variable save_needed is not used for anything else

init.lua

@@ -546,6 +546,7 @@ minetest.register_chatcommand("factions", {
 })
 
 -- Fix factions
+do
 	local save_needed = false
 	for _, fact in pairs(facts) do
 		if not fact.members then
@@ -560,5 +561,6 @@ end
 	if save_needed then
 		save_factions()
 	end
+end
 
 print("[playerfactions] loaded")