qa_openstack: Fix SLE12SP2 repo
qa_openstack: Fix SLE12SP2 repo

Use the SLE12SP2 repository which is now available on the SMT server.

gosipyan/automation,vmoravec/automation,aspiers/automation,vmoravec/automation,vmoravec/automation,aspiers/automation,aspiers/automation,vmoravec/automation,aspiers/automation,gosipyan/automation,SUSE-Cloud/automation,SUSE-Cloud/automation,gosipyan/automation,SUSE-Cloud/automation,gosipyan/automation,SUSE-Cloud/automation