In my eyes, the above looks correct and appropriate to merge (test just in case).

The only alternative if the versionsuffix started with underscore, 
would be something like: (notice the absorption of the underscore)
sources = [('abinit-%s%s.bz2' % (version, versionsuffix), 'tar xfj %s')]

But, I think we can all agree that all ideas here are bit ugly, because the original thingy is such :)