(Reuters) - The name of one of the Boston Marathon bombing suspects, Tamerlan Tsarnaev, was listed on the U.S. government's highly classified central database of people it views as potential terrorists. But the list is so vast that this did not mean authorities automatically kept close tabs on him, sources close to the bombing investigation said on Tuesday. Tsarnaev, 26, was killed in a police shootout early Friday, while his younger brother Dzhokhar, 19, was captured later that day. Prosecutors say the brothers, ethnic Chechens who had been living in the United States for more than a decade, planted two...