gui: /rest/system/browse with no arguments returns drives on Windows (ref #3201)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3203

lib/osutil/drives_unix.go

@@ -0,0 +1,13 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build !windows
+
+package osutil
+
+func GetDriveLetters() ([]string, error) {
+	return nil, nil
+}