mUMBAI, Sept. 5 -- RBI will lock up excess banking cash for longer, stepping up efforts to manage a record liquidity glut fuelled by its drive to attract dollars from overseas Indians. RBI will hold a Rs.7 trillion ($74.1 billion), 30-day variable-rate reverse repo auction Monday. India's banking system is awash with a record Rs.10.5 trillion of excess cash, after RBI exchanged dollars raised by banks from overseas Indians for rupees. P10...