Menu callback; present a form for deleting a date format.
string $date_format_id: The machine name for the date format that may be deleted.
function system_date_delete_format_form($form, &$form_state, $date_format_id) {
$form['date_format_id'] = array(
'#type' => 'value',
'#value' => $date_format_id,
);
$format = system_get_date_formats($date_format_id);
$output = confirm_form($form, t('Are you sure you want to remove the format %name : %format?', array(
'%name' => $format['name'],
'%format' => format_date(REQUEST_TIME, $date_format_id),
)), 'admin/config/regional/date-time/formats', t('This action cannot be undone.'), t('Remove'), t('Cancel'), 'confirm');
return $output;
}