IPN callback sets custom order statuses to failed

[alovitsm]

We use custom order statuses to follow the progress of fulfilment. If a customer has tried to pay twice and only succeeded on the second try, the first payment callback sets the status to failed even if the second payment was successful (or the customer chose another method).

In WC_Gateway_Barion_IPN_Handler::check_barion_ipn(), line 42 only evaluates if a status is processing or completed. Maybe it'd be better to do !$order->has_status(array('pending')) instead of $order->has_status(array('processing', 'completed')) to resolve this for those who use custom statuses.