Display a warning in the site status page when Metatag module is installed and enabled...

Here is print_r() of my $head_elementsin module implementation of hook_html_head_alter()
My site http://kranio.pp.ua.

<?php
/**
 * Implements hook_html_head_alter().
 */
function remove_generator_html_head_alter(&$head_elements) {
  // Remove Generator META tag.
  print_r($head_elements);
  if (isset($head_elements['system_meta_generator'])) {
    unset($head_elements['system_meta_generator']);
  }
}
?>

<pre>
Array
(
    [system_meta_content_type] => Array
        (
            [#type] => html_tag
            [#tag] => meta
            [#attributes] => Array
                (
                    [http-equiv] => Content-Type
                    [content] => text/html; charset=utf-8
                )

            [#weight] => -1000
        )

    [metatag_generator] => Array
        (
            [#theme] => metatag
            [#tag] => meta
            [#id] => metatag_generator
            [#name] => generator
            [#value] => Drupal 7 (http://drupal.org)
            [#attached] => Array
                (
                    [drupal_add_http_header] => Array
                        (
                            [0] => Array
                                (
                                    [0] => X-Generator
                                    [1] => Drupal 7 (http://drupal.org)
                                )

                        )

                )

            [#type] => html_tag
        )

    [metatag_og:type] => Array
        (
            [#theme] => metatag_opengraph
            [#tag] => meta
            [#id] => metatag_og:type
            [#name] => og:type
            [#value] => article
            [#type] => html_tag
        )

    [metatag_og:title] => Array
        (
            [#theme] => metatag_opengraph
            [#tag] => meta
            [#id] => metatag_og:title
            [#name] => og:title
            [#value] => Информация о пользователе
            [#type] => html_tag
        )

    [metatag_og:site_name] => Array
        (
            [#theme] => metatag_opengraph
            [#tag] => meta
            [#id] => metatag_og:site_name
            [#name] => og:site_name
            [#value] => Кранио-сакральная терапия
            [#type] => html_tag
        )

    [metatag_og:url] => Array
        (
            [#theme] => metatag_opengraph
            [#tag] => meta
            [#id] => metatag_og:url
            [#name] => og:url
            [#value] => http://kranio.pp.ua/?q=user
            [#type] => html_tag
        )

)
</pre>

Yes, thanks, am realy have instaled Metatag module. Problem fixed.