LOS ANGELES (Hollywood Reporter) -- CBS is expected to announce today that former "CBS Evening News" anchor Dan Rather will leave the network after 44 years. Rather's contract runs through November, but he is expected to leave CBS immediately to pursue other opportunities. A special tribute to Rather's career is expected to appear on tonight's "CBS Evening News." The move was widely expected in the past few weeks after Rather, 74, had said that he would be leaving CBS after negotiations on a new contract hadn't guaranteed him anything but an office at the network. After leaving "CBS Evening News"...