to fix scandir warning

git-svn-id: https://plugins.svn.wordpress.org/wp-fastest-cache/trunk@947485 b8457f37-d9ea-0310-8a92-e5e31aec5664
v0.8.2.2 is live

git-svn-id: https://plugins.svn.wordpress.org/wp-fastest-cache/trunk@947486 b8457f37-d9ea-0310-8a92-e5e31aec5664