FIX: Site Settings weirdness with back button

app/assets/javascripts/admin/controllers/admin-site-settings.js.es6

@@ -1,7 +1,6 @@
 import debounce from 'discourse/lib/debounce';
 
 export default Ember.Controller.extend({
-  queryParams: ["filter"],
   filter: null,
   onlyOverridden: false,
   filtered: Ember.computed.notEmpty('filter'),

app/assets/javascripts/admin/routes/admin-site-settings.js.es6

@@ -1,6 +1,10 @@
 import SiteSetting from 'admin/models/site-setting';
 
 export default Discourse.Route.extend({
+  queryParams: {
+    filter: { replace: true }
+  },
+
   model() {
     return SiteSetting.findAll();
   },