I was just impatient 
Just re-ran all the tests and things seem to be working again.
Thanks for the fixes @nuclearsandwich.
Edit: could you trigger a build for the abb_driver release job I referenced in the OP? Afaict it should build, but of course I can’t trigger it.
Would there be a way to add some sort of testing for this to the rospkg repository (and other repositories with Python 2 & 3 packages)? This particular case would have been caught by a test which attempts to install the package on all supported platforms.
Perhaps this is already done and I just haven’t checked btw (in fact: I haven’t 
).