Wal-Mart Stores today named Rosalind Brewer president and chief executive of its Sam’s Club unit. She succeeds Brian Cornell, who said he is leaving the position to return to the Northeast for family reasons. Brewer previously was president of the Wal-Mart east business unit where she was responsible for $100 billion in revenue and 500,000 associates. Other executive changes revealed today included Rollin Ford, who was named chief adminitrativwe officer for the conmpany, an...