add filename to progress bar, and display ok/failed at end

This needed plumbing an AssociatedFile through retrieveKeyFileCheap.

Remote/Tahoe.hs

@@ -70,7 +70,7 @@ gen r u c gc = do
 		, name = Git.repoDescribe r
 		, storeKey = store u hdl
 		, retrieveKeyFile = retrieve u hdl
-		, retrieveKeyFileCheap = \_ _ -> return False
+		, retrieveKeyFileCheap = \_ _ _ -> return False
 		, removeKey = remove
 		, checkPresent = checkKey u hdl
 		, checkPresentCheap = False