deleting old 2.4 readme file

git-svn-id: https://plugins.svn.wordpress.org/a-very-simple-captcha/trunk@817457 b8457f37-d9ea-0310-8a92-e5e31aec5664
added 2.4.1 readme

git-svn-id: https://plugins.svn.wordpress.org/a-very-simple-captcha/trunk@817459 b8457f37-d9ea-0310-8a92-e5e31aec5664