Add deleteFileFromStorage lambda to DownloadMiddleware.

Author: mcarare

app/src/main/java/org/mozilla/reference/browser/components/Core.kt

@@ -100,7 +100,7 @@ class Core(
     val store by lazy {
         BrowserStore(
             middleware = listOf(
-                DownloadMiddleware(context, DownloadService::class.java),
+                DownloadMiddleware(context, DownloadService::class.java, { false }),
                 ThumbnailsMiddleware(thumbnailStorage),
                 ReaderViewMiddleware(),
                 RegionMiddleware(