Respond to user deletion.
This hook is invoked from user_delete_multiple() after field_attach_delete() has been called and after the user has been removed from the database.
Modules should additionally implement hook_user_cancel() to process stored user data for other account cancellation methods.
$account: The account that has been deleted.
Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.
function hook_user_delete($account) {
drupal_set_message(t('User: @name has been deleted.', array(
'@name' => $account->name,
)));
}