By Bill Rigby (Reuters) – Apple Incs profit and margins slid despite selling 33.8 million iPhones in its September quarter, and greater China revenue climbed just 6 percent even though two smartphone models hit store shelves in its second-largest market last month. The unremarkable quarterly numbers prompted some disappointed investors to cash in recent gains in the stock, which slid 5 percent at one stage after-hours on Monday. …