Word of a big exec shakeup at RIM leaked out just ahead of the company's quarterly earnings late last month -- something that was then quickly confirmed in said earnings report. It looks like that wasn't the end of it though, as RIM has now also confirmed the departures of two more high-level executives. That includes Senior Vice President Alan Brenner, who will be leaving after an unspecified transition period, and Tenille Kennedy, a VP for RIM's BBM service who has already l