On the same day CBS announced the appointment of an independent commission to investigate the circumstances surrounding forged documents aired during a "60 Minutes" segment, the company girded for legal action in the matter. On Wednesday, Anthony Bongiorno, counsel for the beleaguered network ordered a legal hold on all tapes and material relating to the report.Bongiorno did not return a telephone call seeking additional information, but a Talon News source reported that the hold was a response to legal action that was expected following the independent commission's investigation. Bill Burkett, the admitted source of the forgeries, is threatening to sue...