this places the aria label on the menu div as asked by some vendors d…#1694

micahgodbolt merged 3 commits intomicrosoft:mastermicrosoft/fluentui:masterfrom

petdun2519:users/petdun/placeAriaLabelOnMenuDivpetdun2519/office-ui-fabric-react:users/petdun/placeAriaLabelOnMenuDivCopy head branch name to clipboard