T-Mobile US Inc. will elevate its chief operating officer, Srini Gopalan, to the chief executive officer spot on Nov. 1, replacing Mike Sievert, who has held the job for nearly six years.Sievert, 56, will become vice chairman, a new position in which he’ll continue to advise management on strategy, the telecom carrier said in a statement Monday.Gopalan, 55, joined T-Mobile in March. He was previously CEO of the German unit of Deutsche Telekom, T-Mobile’s controlling shareholder. German media reported in Jun ...