Code review comment for lp:~sjakthol/software-properties/fix-1037916

Thanks for the explanation. Using os.path.join does seem reasonable.
However, a style point: using "from os.path import join" inside a
function isn't very PEP-8-ish - you only need to do that kind of thing
in the case where the import must be deferred until the function is
first called (usually only for circular or conditional imports).

I suggest instead:

 * 'import os' at the top of the file
 * call os.path.join rather than join

Could you make and test that change and I'll be happy to sponsor it?