Winning percentage is the same before each match. Because India is a big opponent for any team. There is a big difference between India and Bangladesh team position. What ever the odds or percentage when the game will be started everything will be change very quickly. That is mainly depend on the performance. Since Bangladesh has won two matches, India will definitely protect themselves from the Whitewash. But if Bangladesh can give their best, there is no guarantee that they will not lose in this match.
Bangladesh need to focus on there fielding. In the last game they dropped catches of ROHIT at very crucial stage and are lucky to still win the game. They should learn how to handle pressure situations. I would say Bangladesh have a golden chance to Whitewash India.