Campbell Soup Co. reported adjusted earnings of 52 cents last quarter, below analysts’ projection of 55 cents. Sales slipped to $1.66 billion, compared with an estimate of $1.69 billion. It didn’t help that Warren Buffett gave off bad vibes about the possibility that Campbells might benefit from a merger by dismissing the notion that Kraft Heinz Co. would buy a company like Mondelez International Inc. With prospects weak for the CPG business, investors sent shares of Campbell down 6.5 percent at one point, the biggest one-day plunge since February.