add private mode

src/client/js/services/AdminGeneralSecurityContainer.js

@@ -68,7 +68,7 @@ export default class AdminGeneralSecurityContainer extends Container {
    * @return {bool} isWikiModeForced
    */
   get isWikiModeForced() {
-    return this.state.wikiMode === 'public';
+    return this.state.wikiMode === 'public' || this.state.wikiMode === 'private';
   }
 
   /**