Initialize Sunny_Post_Purger Only When Needed

git-svn-id: https://plugins.svn.wordpress.org/sunny/trunk@961959 b8457f37-d9ea-0310-8a92-e5e31aec5664
Tag 1.2.4

git-svn-id: https://plugins.svn.wordpress.org/sunny/trunk@961960 b8457f37-d9ea-0310-8a92-e5e31aec5664