Make downstream issues show their error in the UI

endpoints/api/secscan.py

@@ -47,7 +47,7 @@ def _security_status_for_image(namespace, repository, repo_image, include_vulner
     else:
       data = secscan_api.get_layer_data(repo_image, include_features=True)
   except APIRequestFailure as arf:
-    raise DownstreamIssue({'message': arf.message})
+    raise DownstreamIssue(arf.message)
 
   if data is None:
     raise NotFound()