jayvdb added a comment.
@hashar, we have used the precise sudo-less Travis images because they are much quicker to boot than the precise sudo and trusty images, and it is common for 6 job on these images to run concurrently, whereas all other images are typically restricted to 3 jobs running
Xqt added a project: Upstream.Xqt added a comment.
Looks like this problem is upstream since it was introduced between build 3574 an 3574:
3574
https://travis-ci.org/wikimedia/pywikibot-core/builds/153181059
https://travis-ci.org/wikimedia/pywikibot-core/jobs/153181060
3575
