Remove run-time dependency on fixtures module by the nova baremetal

Tripleo still uses this baremetal driver. The dependency on the python fixtures
was introduced by https://review.openstack.org/#/c/71219/

This dependency is causing devtest to stop working.

Change-Id: Id6deccce13698b083af492635ff88533c059fd35
Merge "Remove run-time dependency on fixtures module by the nova baremetal"