Only set the xml slug if it isn't already set

common/lib/keystore/xml.py

@@ -40,6 +40,7 @@ class XMLModuleStore(ModuleStore):
                         except:
                             log.exception("Unable to parse xml: {xml}".format(xml=xml))
                             raise
+                        if xml_data.get('slug') is None:
                             if xml_data.get('name'):
                                 xml_data.set('slug', Location.clean(xml_data.get('name')))
                             else: