qa_openstack: remove fallback hostname
qa_openstack: remove fallback hostname

The variable was not used and on "http://fallback.suse.cz/ibs/Devel:/"
is no Cloud directory available. So couldn't be used anyway.

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