XMLExportImport.py: add compatibility to export a dict type property value.

product/ERP5Type/XMLExportImport.py

@@ -118,7 +118,7 @@ def Base_asXML(object, root=None):
             for word in value]
         sub_object.append(marshaller(value))
       elif prop_type in ('text', 'string',):
-        if type(value) in (tuple, list):
+        if type(value) in (tuple, list, dict):
           sub_object.text = str(value)
         else:
           sub_object.text = unicode(escape(value), 'utf-8')