Although I don’t see the point. You could “disable” that action directly by going to the following directory: wp-includes/pluggable.php
Then search for “wp_logout” and comment out out as follows:
function wp_logout() {
//wp_clear_auth_cookie();
//do_action('wp_logout');
}
Not sure exactly where you want to remove the button from, but if it’s from the admin bar you could always check out: how to add or remove link from the admin bar