t/old-base.t fails on some systems without /tmp

[Hugmeir]

The newlocal_test() in t/old-base.t doesn't (can't) use File::Temp for File::Spec, and because of that it fails on systems without /tmp (Android, Blackberry 10) unless they have a special case in the code.

A quick fix is to add a 'return 1 if ! -e $tmpdir' right after $tmpdir is guessed, which makes the test pass; I suppose that the proper fix would be to create your own tmpdir under pwd and then removing it, but that seems like too much work for too little gain.