Switch Master to SLE15-SP1
Switch Master to SLE15-SP1

There is really no point in trying to make SLE_15 work (and
it currently fails to build)

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