Catch ValueErrors thrown when attempting to remove a file twice

[Jake-Carter]

Fixes #3313

This PR catches ValueError to improve the safety of the list.remove calls, as they may attempt to remove the same file multiple times.

I think this is more acceptable than...

if a in files: files.remove(a)

... because files can be a really large list to iterate across.

[oprypin]

Thanks. I thought it would be impossible for it to try to delete the same file twice, and anyway if there are 3 files, it should delete 2 of them rather than just catch an error from deleting 1 file twice. So I should look for a better fix but this is good for now