Comment 5 for bug 1529594

I'd suggest that we should lower the oslo.messaging bound in upper-constraints on stable/liberty to 2.5.0 which would align that version with the stable/liberty g-r version on oslo.service, which is >=0.7.0 (which would also match what's in keystone server requirements).

oslo.messaging 3.0.0 just doesn't really work with older versions of oslo libraries (it would work with the version of oslo.service that's in u-c in stable/liberty, 1.1.0).