* India considering tweaking clause on equity - sources * India government spokesman says policy change being considered * Past changes have hit Amazon, Walmart NEW DELHI, Jan 19 (Reuters) - India is considering revising its foreign investment rules for e-commerce, three sources and a government spokesman told Reuters, a move that could compel players, including Amazon.com Inc, to restructure their ties with some major sellers. The government discussions coincide with a growing number of complaints from India’s brick-and-mortar retailers, which have for years accused Amazon and Walmart Inc-controlled Flipkart of creating complex structures to bypass federal rules, allegations the U.S. companies deny.