S390 builds are booting forever

[hugovk]

Same here on these, the issue started during Saturday’s database maintenance:

• https://travis-ci.com/github/ultrajson/ultrajson/builds/154359958
• https://travis-ci.com/github/ultrajson/ultrajson/jobs/301263815

It was also happening on my fork, but that’s now ok:

• https://travis-ci.org/github/hugovk/ultrajson/builds/665944472

(I mentioned it in Ppc64le builds stuck in queue, but that’s mainly for ppc64le which is ok now.)