In a move designed partly to balance their budget for the coming season, the Calgary Flames traded centre Chris Drury and left winger Steve Begin to the Buffalo Sabres yesterday for defenceman Rhett Warrener and centre Steven Reinprecht. The move was precipitated by the Flames inability to sign Drury, 26, to a contract extension. Drury, who was earning $2.5-million, was seeking a raise in excess of $4-million a season.