PBR has a circle dependency

[Domen Kožar]

PBR 1.81 depends on teststools, which depends on unittest2, which depends on traceback2, which depends on pbr.

It's unwise to have circular dependencies and makes package management hard.

[Clark Boylan (cboylan)]

This is only true for running the test suite. Which I think means for packaging you can set the dependency to be traceback2 depends on PBR then to run the tests just install PBR first before running the tests (in fact this is how we run the tests upstream, tox installs PBR to the test env).

[Ben Nemec (bnemec)]

Does anyone object to that solution? I don't know that we can reasonably drop the dependency on testtools so I'm not sure how we could fix this otherwise anyway.