Description of problem:
No "allowVolumeExpansion" field in "oc describe sc"

Version-Release number of selected component (if applicable):
openshift v3.10.0-0.15.0
kubernetes v1.9.1+a0ce1bc657

How reproducible:
Always

Steps to Reproduce:
1. Enable feature gate "ExpandPersistentVolumes" and admission controller "PersistentVolumeClaimResize"
2. Create a storageclass with allowVolumeExpansion=true
# oc export sc standard
allowVolumeExpansion: true
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  annotations:
    storageclass.beta.kubernetes.io/is-default-class: "true"
  creationTimestamp: null
  name: standard
parameters:
  fstype: xfs
provisioner: kubernetes.io/cinder
reclaimPolicy: Delete

Actual results:
# oc describe sc standard
Name:            standard
IsDefaultClass:  Yes
Annotations:     storageclass.beta.kubernetes.io/is-default-class=true
Provisioner:     kubernetes.io/cinder
Parameters:      fstype=xfs
ReclaimPolicy:   Delete
Events:          <none>

Expected results:
There is a "allowVolumeExpansion" field in the output.

Master Log:

Node Log (of failed PODs):

PV Dump:

PVC Dump:

StorageClass Dump (if StorageClass used by PV/PVC):

Additional info: