Update the Plugin URI

git-svn-id: https://plugins.svn.wordpress.org/redirect-network-login/trunk@873489 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update README.txt

git-svn-id: https://plugins.svn.wordpress.org/redirect-network-login/trunk@873490 b8457f37-d9ea-0310-8a92-e5e31aec5664