(Reuters) - The Bank of Japan kept interest rates steady on Friday but decided to start selling its holdings of risky assets, taking another step forward in phasing out remnants of its massive stimulus programme. Two of the BOJ's nine board members dissented to the central bank's decision to keep short-term interest rates at 0.5% and proposed, unsuccessfully, to hike borrowing costs to 0.75%. At the two-day meeting that ended on Friday, the BOJ decided to sell its holdings of exchange-traded funds (ETF) ...