[test] Replace logilab-common's with_tempdir by tempfile.TemporaryDirectory logilab-common's with_tempdir decorator, which is considered harmful (see https://www.logilab.org/ticket/8267966). Rely on backports.tempfile to provide TemporaryDirectory on Python 2. Re-export it in testlib module for convenience.

version=3
opts=uversionmangle=s/(rc|a|b|c)/~$1/ \
https://pypi.debian.net/cubicweb/cubicweb-(.+)\.(?:zip|tgz|tbz|txz|(?:tar\.(?:gz|bz2|xz)))