Sanitize result backend in celery report output. Closes #2812

celery/app/utils.py

@@ -221,7 +221,8 @@ def bugreport(app):
         py_v=_platform.python_version(),
         driver_v=driver_v,
         transport=transport,
-        results=app.conf.CELERY_RESULT_BACKEND or 'disabled',
+        results=maybe_sanitize_url(
+            app.conf.CELERY_RESULT_BACKEND or 'disabled'),
         human_settings=app.conf.humanize(),
         loader=qualname(app.loader.__class__),
     )