Fix ssh key adding to ardana
Fix ssh key adding to ardana

The previous PR in https://github.com/SUSE-Cloud/automation/pull/2458
was broken and untested. Fix it up by ensuring that we
read the files prior overwriting them.

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