Hide instead of deleting unused settings

packages/rocketchat-lib/settings/server/publication.coffee

@@ -2,6 +2,7 @@ Meteor.publish 'settings', (ids = []) ->
 	console.log '[publish] settings'.green
 
 	filter =
+		hidden: { $ne: true }
 		public: true
 
 	if ids.length > 0

server/startup/settings.coffee

@@ -1,4 +1,4 @@
 # Remove runtime settings (non-persistent)
 Meteor.startup ->
-	RocketChat.models.Settings.remove({ ts: { $lt: RocketChat.settings.ts } })
+	RocketChat.models.Settings.update({ ts: { $lt: RocketChat.settings.ts } }, { $set: { hidden: true } })