Fix zoom schema: auth_url is optional

diff --git a/xml/schema/filter_zoom.rnc b/xml/schema/filter_zoom.rnc
index 68373ae..06d0694 100644 (file)
--- a/xml/schema/filter_zoom.rnc
+++ b/xml/schema/filter_zoom.rnc
@@ -7,7 +7,7 @@ filter_zoom =
   attribute id { xsd:NCName }?,
   attribute name { xsd:NCName }?,
   element mp:torus {
-    attribute auth_url { xsd:string },
+    attribute auth_url { xsd:string }?,
     attribute url { xsd:string },
     attribute content_url { xsd:string }?,
     attribute realm { xsd:string },