Fix bug: no way to reset key alert codes without deleting the key and resaving it. Now when an alert is found, we reverify that the key is still in alert state before we show the alert in config page. If key is fine, we automatically clear the alert code in the plugin.

git-svn-id: https://plugins.svn.wordpress.org/akismet/trunk@1033930 b8457f37-d9ea-0310-8a92-e5e31aec5664