An openstack network provider can not be created using rest api v3.
The problem is the type property which has been added. It is not present in v3, and must be added the v3 adapter.
This bug report has Keywords: Regression or TestBlocker.
Since no regressions or test blockers are allowed between releases, it is also being identified as a blocker for this release. Please resolve ASAP.
oVirt 4.0.0 has been released, closing current release.