The /api endpoint does not exists anymore in ovirt-engine's master. ovirt-image-uploader should point to /ovirt-engine/api, otherwise users will get a 404 error.
I guess iso-uploader and log-collector are affected as well. If so, please open a bz for them too.
(In reply to Sandro Bonazzola from comment #1)
> I guess iso-uploader and log-collector are affected as well. If so, please
> open a bz for them too.
iso-uploader is affected, see bug #1264542. log-collector already uses the correct endpoint.
engine-image-uploader is correctly pointing to ovirt-engine/api endpoint but command fails due to bz1349774
oVirt 4.0.0 has been released, closing current release.