The build was repeatedly broken over the last week.

Two of the build breakages have been fixed.

I think one was caused by changes to WMF site configuration.

https://travis-ci.org/wikimedia/pywikibot-core/builds/30824554

And the other caused by merging a fix without checking the tests
worked correctly.

https://travis-ci.org/wikimedia/pywikibot-core/builds/30831527

And there is still one more bug that needs to be fixed.

https://bugzilla.wikimedia.org/show_bug.cgi?id=68564

Or we need to roll back the several commits which caused categories to
be broken.

As we may need to roll back several commits, could we please not check
in new code while the build is broken.