WASHINGTON (Reuters) -The U.S. Treasury issued a special waiver on Friday to allow investors with insurance against a Russian default, known as Credit Default Swaps, to receive their payouts. The normally straightforward process of CDS payouts was thrown into chaos in June when Washington said its sanctions on Russia represented a total ban on buying Moscow’s debt. An investor who buys a CDS contract usually hands over the underlying bond to the bank or fund that sold them the CDS when a default happens. It traditionally involves an auction to determine the price, but under the sanctions that …