The bespectacled face of Mustapha Limam Chafi, with his trademark round gold-rimmed glasses, is a familiar sight at all the grand hotels along Doha's waterfront promenade, from the Saint-Regis to the Shangri-La, and the W. Every two months, the Mauritanian-born diplomat is invited by the Qatari monarch to stay, all expenses paid, in return for his counsel.