Updated openstack/openstack
Project: openstack/requirements  3eaf108264f32bab51adff6c3a6ac0427ac3c119

Bump up minimum cliff version to 1.6.0

OpenStackClient uses --max-width and the value formatter, both introduced
in 1.6.0.

Change-Id: I17a9fd335e2a3b746ddb069f13bf6cf710b38118