get error description from error key vs error_description key

Signed-off-by: Greg <werner.greg@gmail.com>

jupyterhub/services/auth.py

@@ -371,9 +371,9 @@ class HubAuth(SingletonConfigurable):
             )
             app_log.warning(r.text)
             msg = "Failed to check authorization"
-            # pass on error_description from oauth failure
+            # pass on error from oauth failure
             try:
-                description = r.json().get("error_description")
+                description = r.json().get("error")
             except Exception:
                 pass
             else: