Add/Change SECRET_KEY in wp-config.php for WP 2.5.x installs
Adds or changes the random SECRET_KEY in your WordPress wp-config.php file, if file permissions allow it. NOT needed on new installs unless you want to change the key; it's useful on upgrades where you're reusing the old wp-config.php file. Just activate. On success the plugin will add the key, log you out, and then deactivate itself. On failure, it will give you a random key to add by hand. Note: if any problems, just delete this file or rename it and refresh your browser.