tweak system and os_type for OVA

[ashcrow]

Backport of #528

[imcleod]

/lgtm

[miabbott]

👍

[bgilbert]

Noting for the record that this is not a cosmetic change.

[imcleod]

My read of that page, initially, is that newer HW revisions have higher limits on certain resources, and a larger set of available virtual HW more generally.

I can't see anything net-new on the v13 hardware that we are attempting to use in our OVA, and our memory and CPU settings are, of course, not hitting the limits.

Do we/you have actual examples of an OVA that is otherwise identical in terms of size and virtual HW configuration, that actually behaved differently just because of the change in virtual HW version?

[bgilbert]

Yes, coreos/bugs#1583. That was in the opposite direction, of course; my point is that virtual hardware changes can exercise different code paths in the kernel.