Fix problems with oslo.config
Fix problems with oslo.config

Fix import error. No module named cfg.

Change-Id: Iab601d335fd4b357931c3ce80c70b516923319b6

openstack/monasca-persister,stackforge/monasca-persister,openstack/monasca-persister,stackforge/monasca-persister,openstack/monasca-persister,sapcc/monasca-persister,stackforge/monasca-persister