tailscale: update tailfs file and package names (#11590)

This change updates the tailfs file and package names to their new
naming convention.

Updates #tailscale/corp#16827

Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>

drive/driveimpl/dirfs/removeall.go

@@ -0,0 +1,15 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package dirfs
+
+import (
+	"context"
+	"os"
+)
+
+// RemoveAll implements webdav.File. No removal is supported and this always
+// returns os.ErrPermission.
+func (dfs *FS) RemoveAll(ctx context.Context, name string) error {
+	return &os.PathError{Op: "rm", Path: name, Err: os.ErrPermission}
+}