Github user soralee commented on the issue:
https://github.com/apache/zeppelin/pull/2042
cc @1ambda @AhyoungRyu :smile:
In my case, I fixed same error with click `Delete all repository cache` as
explained in [Travis
document](https://docs.travis-ci.com/user/caching/#Clearing-Caches)
I guess this error is occurred by cache of Travis.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
