Update oc to use v3.9.0

We have new [release](https://github.com/openshift/origin/releases/tag/v3.9.0) of oc in last week. Currently we are using [`v3.9.0-alpha.3`](https://github.com/arquillian/arquillian-cube/blob/master/.travis.yml#L7), update it to use `v3.9.0`