By Alexei Oreskovic SAN FRANCISCO (Reuters) – Yahoo Inc cannot seem to part ways with Alibaba. Yahoo said on Tuesday that it would keep a bigger-than-expected chunk of its stake in Alibaba when the Chinese e-commerce company goes public later this year. It remains a very large fig leaf, Pivotal Research Group analyst Brian Wieser said of Yahoos Alibaba stake, which he said obscures Yahoos weak results.