Update WPCOM_Liveblog_Socketio_Loader::is_enabled() documentation now…

… that private Liveblog posts is supported

I forgot to update this method documentation when support to private Liveblogs posts was added.

classes/class-wpcom-liveblog-socketio-loader.php

@@ -126,10 +126,8 @@ public static function show_old_php_for_socketio_error() {
 
 	/**
 	 * Return true if viewing a liveblog post, Socket.io support is
-	 * enabled, socket.io-php-emitter is installed and connected to the
-	 * Redis server and post is public. For now we only support Socket.io
-	 * for public posts since there is no way to tell in the Socket.io
-	 * server if a client has permission or not to see a Liveblog post.
+	 * enabled and socket.io-php-emitter is installed and connected to the
+	 * Redis server.
 	 *
 	 * @return bool
 	 */