The distro packages of nose and pylint depend on python-setuptools
on some platforms, and on some of those platforms (at least CentOS
6.x) you can't resolve dependencies on python-setuptools properly if
you've forcibly removed it already (as we do on our CI workers). It
appears that any current upstream use of these tools in relation to
DevStack-based testing is now relying on tox and pip to obtain them
instead.
Change-Id: Ibd16ac550c90364115caf57fae4f5f4cb5d5f238
091b42b7da