Clearly Rashid and Ali troubled the Indian batsmen in the ODI's probably more than anyone anticipated they would, and the selectors thought, why change something that seems to be working.
FWIW, India have a lot of right-handers, so selecting two off-spinners would be a brainless decision. So it was either going to be Leach or Rashid (or some other SLA or leggie), and I guess their gut instincts told them that Rashid might be the better bet. Whether they're right, who knows.