Diageo, the world's leading alcohol company announced today that it has completed the sale of the Glen Ellen Winery to a company managed by The Wine Group.   The transaction, which was announced on March 18, was structured as an asset purchase, and included the sale of Glen Ellen along with the MG Vallejo brands, the worldwide trademark rights, and all the Glen Ellen and MG Vallejo inventory. Diageo Chateau & Estate Wines Company, based in Napa, California, had managed Glen Ellen.