Finish the Lock and Unlock feature for webdav.

code/tool/webdav/webdav.go

@@ -84,7 +84,7 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 func (h *Handler) lock(now time.Time, root string) (token string, status int, err error) {
 	token, err = h.LockSystem.Create(now, LockDetails{
 		Root:      root,
-		Duration:  infiniteTimeout,
+		Duration:  InfiniteTimeout,
 		ZeroDepth: true,
 	})
 	if err != nil {