Make the CI happy again

[Fokko]

Hi all,

I'd like to propose the following changes:

• Move from Oracle to OpenJDK completely. Something is off with the Oracle builders of Travis: https://travis-ci.org/airlift/airbase/jobs/592909648
• Set JDK14 Early Access to allow failure. This will run the build but ignore the result. Therefore the badge on the repository will be green, looking all good won't upset any users. The current issue that we're seeing is spotted by Gradle and Groovy as well and seems to be something with the JDK: JDK 14 support gradle/gradle#10248

Cheers, Fokko

[martint]

Looks good, but can you change the commit message to something more descriptive? (e.g., "Do not report failures for early access JDK")

[Fokko]

Thanks for the response @martint, I've updated the commit message.

[findepi]

@Fokko did you push? (Github doesn't indicate that)

[Fokko]

@findepi My mistake, I've created a PR from my master branch by accident (which I shouldn't). I've opened a PR in #189