By Leika Kihara and Makiko Yamazaki TOKYO (Reuters) - The Bank of Japan decided on Friday to start selling its holdings of risky assets and two board members voted against keeping interest rates steady, suggesting the bank would phase out its massive monetary stimulus sooner than first thought. While the central bank kept short-term interest rates at 0.5%, board members Hajime Takata and Naoki Tamura proposed, unsuccessfully, a hike to 0.75% in a move markets saw as a prelude to a near-term increase in b ...