SAN FRANCISCO (Reuters) – Alibaba Group Holding Ltd overhauled its pact with the parent of its payments affiliate Alipay, boosting the Chinese e-commerce giants potential gain if Alipay is sold or goes public, according to an amended Alibaba filing on Tuesday. Alibaba, which is set to go public in New York later this year, also agreed to sell its small and medium enterprise loan business for $518 million cash to Alipays parent company, called the Small and Micro Financial Services Company. The deal was revised on Aug. 12, Alibaba said in the securities filing. …