Fix imports on Python 3
Fix imports on Python 3

On Python 3, imports are absolute by default.

Because of these invalid imports, tests don't run anymore on
Python 3, since tests cannot be loaded.

Change-Id: Ib11a09432939df959568de400f60dfe981d0a403

openstack/cue,stackforge/cue,stackforge/cue,openstack/cue,openstack/cue,stackforge/cue