Form submission handler for comment_confirm_delete().
function comment_confirm_delete_submit($form, &$form_state) {
$comment = $form_state['comment'];
// Delete the comment and its replies.
comment_delete($comment->cid);
drupal_set_message(t('The comment and all its replies have been deleted.'));
watchdog('content', 'Deleted comment @cid and its replies.', array(
'@cid' => $comment->cid,
));
// Clear the cache so an anonymous user sees that his comment was deleted.
cache_invalidate_tags(array(
'content' => TRUE,
));
$form_state['redirect'] = "node/{$comment->nid}";
}