Description of problem:
when provision mariadb-apb in prod plan, the data doesn't sync to pv.

Version-Release number of selected component (if applicable):


How reproducible:
aways

Steps to Reproduce:
1. build a docker runtime env
2. provision mariadb-apb in prod plan, it will succeed.
3. check data in mariardb pod
4. check data in pv node

Actual results:
step 4: 
# oc get pvc
NAME                                           STATUS    VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
mariadb-c21f54d8-9c82-11e8-a0ff-0a580a8000bb   Bound     pvc-e9cc5630-9c82-11e8-bc1b-fa163eebd417   1Gi        RWO            standard       13m

# oc get pod -o wide
NAME                                                   READY     STATUS    RESTARTS   AGE       IP            NODE                   NOMINATED NODE
mariadb-c21f54d8-9c82-11e8-a0ff-0a580a8000bb-2-pd648   1/1       Running   0          8m        10.129.0.67   qe-zitang-810-node-1   <none>

# ssh to the qe-zitang-810-node-1
go to pv mount file
# mount | grep pvc-e9cc5630-9c82-11e8-bc1b-fa163eebd417
/dev/vdb on /var/lib/origin/openshift.local.volumes/pods/7deef55a-9c83-11e8-bc1b-fa163eebd417/volumes/kubernetes.io~cinder/pvc-e9cc5630-9c82-11e8-bc1b-fa163eebd417 type xfs (rw,relatime,seclabel,attr2,inode64,noquota)

[root@qe-zitang-810-node-1 ~]# cd /var/lib/origin/openshift.local.volumes/pods/7deef55a-9c83-11e8-bc1b-fa163eebd417/volumes/kubernetes.io~cinder/pvc-e9cc5630-9c82-11e8-bc1b-fa163eebd417
[root@qe-zitang-810-node-1 pvc-e9cc5630-9c82-11e8-bc1b-fa163eebd417]# ll
total 0
drwxr-sr-x. 2 root       1000440000 6 8月  10 05:55 data
srwxrwxrwx. 1 1000440000 1000440000 0 8月  10 05:55 mysql.sock

[root@qe-zitang-810-node-1 pvc-e9cc5630-9c82-11e8-bc1b-fa163eebd417]# ll data
total 0

data not synced to pv.

Expected results:
data synced to pv.

Additional info:
if changing dc mountPath to '/var/lib/mysql/data', the data in mariadb pod can 
sync with pv