This may be one of the last chances you get to buy a stock you absolutely know is Buffett-approved.Warren Buffett's time as Berkshire Hathaway's (BRK.A +1.34%) (BRK.B +1.37%) chief executive and its chief stock-picker may be nearing its end. But he's still in charge, so any changes he wanted to make to the conglomerate's portfolio before his exit would have likely been made by now. The names Berkshire is still holding suggests everyone's in agreement that they're worth holding onto, and that's a pretty big ...