Pat Riley was adamant. He’s not thinking about coaching. Unless he changes his mind. Unlikely as it seems, the twice-retired Hall of Fame coach might contemplate un-retiring again. Insisting his focus is on this summer’s NBA free-agent bonanza and nothing else, the Miami Heat president acknowledged Monday that it’s possible he could return to the sideline, despite saying when he stepped down in April 2008, “I don’t want to do this anymore.”