General Mills Inc. reported weaker-than-expected sales for the fourth quarter of fiscal 2015 and said profits were cut in half as it took a big asset-impairment charge related to its Green Giant vegetable business. The Golden Valley-based company reported earnings of $186.8 million , or 30 cents per share, for the quarter, down from $404.6 million, or 65 cents per share, in the same period a year ago.