Delete a configured date type.
function system_delete_date_format_type_form_submit($form, &$form_state) {
if ($form_state['values']['confirm']) {
$type_info = system_get_date_types($form_state['values']['format_type']);
system_date_format_type_delete($form_state['values']['format_type']);
drupal_set_message(t('Removed date type %type.', array(
'%type' => $type_info['title'],
)));
$form_state['redirect'] = 'admin/config/regional/date-time';
}
}