Fix for MvcBrowserCaching not working on 8.1 and 8.2

MvcBrowserCaching.cs

public class MvcBrowserCaching : GetPageRenderingProcessor
    {
        public override void Process(GetPageRenderingArgs args)
        {
            Assert.ArgumentNotNull((object)args, "args");
            Profiler.StartOperation("Update browser caching headers.");
            HttpContext currentContext = HttpContext.Current;
            Item currentItem = PageContext.CurrentOrNull.Item;

            if (currentContext == null)
                return;

            MvcBrowserCaching.SetCacheHeaders(currentContext);
            if (currentItem != null)
                MvcBrowserCaching.SetUpdateHeaders(currentItem, currentContext);
            Profiler.EndOperation();
        }

        private static void SetCacheHeaders(HttpContext currentContext)
        {
            if (Context.Site == null && !Settings.DisableBrowserCaching || Context.Site != null && !Context.Site.DisableBrowserCaching)
                return;
            Tracer.Info((object)"Adding Http headers to disable caching.");
            currentContext.Response.Cache.SetNoStore();
            currentContext.Response.Cache.SetCacheability(HttpCacheability.NoCache);
        }

        private static void SetUpdateHeaders(Item item, HttpContext currentContext)
        {
            DateTime date = item.Statistics.Updated;
            if (date > DateTime.UtcNow)
                date = DateTime.UtcNow;
            Tracer.Info((object)"Adding Http header to indicate last modification.", (object)("Date: " + (object)date + " (UTC)."));
            currentContext.Response.Cache.SetLastModified(date);
        }
    }