packaging: setup: use public key for ssh authentication

Use public key for ssh authentication instead of root
password wich is now a deprecated authentication method.

Require sdk >= 3.3.0.4 for having API support.

Related-To: http://gerrit.ovirt.org/18002

Change-Id: I4ba78d92d961fe763208f10a725876a4c081a70f
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>