(Reuters) - AT&T Inc said on Friday it named Seagate Technology Plc chairman Stephen Luczo to its board, days after the second-largest U.S. wireless phone carrier by subscribers announced it would add two new board members.The company earlier this week also unveiled a three-year strategic plan that included selling up to $10 billion (£7.73 billion) worth of businesses next year and paying off all its debt from the purchase of Time Warner, bowing to pressure from activist investor Elliott..