Exclude pbr 2.1.0 from dependencies [WAL-698]
Exclude pbr 2.1.0 from dependencies [WAL-698]

python-neutronclient requires pbr >= 2.0.0 and cliff >= 2.3.0
cliff 6.2.0 requires pbr>=2.0.0,!=2.1.0
Therefore a pbr 2.1.0 has to be excluded explicitly until it is fixed in
neutronclient.

opennode/nodeconductor-openstack