crowbar-prep.sh: improve help text
crowbar-prep.sh: improve help text

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