In a year of missteps across its trading business, Goldman Sachs finds itself in a dicey situation again. This time, the bank’s credit trading desk is caught in the middle of a raging battle among hedge funds over the debt of big U.S. homebuilder Hovnanian Enterprises Inc. It was ignited by Blackstone Group LP’s credit unit, GSO Capital Partners, which is trying to convince the builder to accept a bond refinancing package. GSO’s plan would trigger payments on default insurance that it bought in the credit derivatives market. Goldman’s problem?