A former top Halliburton executive will serve 2 1/2 years in prison after pleading guilty in Houston federal court to orchestrating a $180 million bribery scheme to secure $6 billion in natural gas deals in Nigeria between 1995 and 2004, the Justice Department announced Thursday.Albert “Jack” Stanley is the former CEO of KBR, a Halliburton subsidiary at the time of the bribes; he...