mkcloud: avoid malformatted ssh key injection
mkcloud: avoid malformatted ssh key injection

So far it appended a suffix which was never used for anything,
and with https://github.com/crowbar/crowbar-core/pull/1696 merged
it became more strict in what it accepted.

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