It's all for the sake of appearances, well in character for the lot. Livingstone doesn't think he's ever said anything untoward, Corbyn is of the same opinion but he is still sacrificing him to look tough on this anti-Semitism thing within the party, Livingstone has told him he'll go quietly because he can't be bothered to go through the whole charade at his age.
Whether Corbyn is pushing him out as part of his bid to gain full control over the ranks is something our Labourite correspondents are better positioned to judge on. Let us know if that is the case, we know there are a few currents at play under the plates.