fix sorting for python 3

demos/collect.py

@@ -18,4 +18,4 @@ for f in glob.glob("../*/*.demoinfo.yaml"):
         })
     except:
         logging.exception("failure for file %s",f)
-json.dump({'data':sorted(data)}, sys.stdout, indent = 2, sort_keys=True)
+json.dump({'data':sorted(data, key=lambda x: json.dumps(x, sort_keys=True))}, sys.stdout, indent = 2, sort_keys=True)