Automatic merge from submit-queue

fix group in create clusterrolebinding

group lost.

```
#kubectl create clusterrolebinding test --clusterrole=a --group=b
clusterrolebinding "test" created

#kubectl get clusterrolebinding test -o yaml
apiVersion: rbac.authorization.k8s.io/v1alpha1
kind: ClusterRoleBinding
metadata:
  creationTimestamp: 2016-12-20T03:13:24Z
  name: test
  resourceVersion: "284"
  selfLink: /apis/rbac.authorization.k8s.io/v1alpha1/clusterrolebindingstest
  uid: 44d3476d-c662-11e6-a439-7427ea6f0fe3
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: a
subjects: null
```