Automatic merge from submit-queue

storageclass ceph add imageformat parameter

**What this PR does / why we need it**:
Add a imageformat parameter for StorageClass(ceph rbd)

k8s hard coded ceph imageformat 1, according to [ceph manual](http://docs.ceph.com/docs/master/man/8/rbd/), imageformat 1 was deprecated, we should add an extra ceph parameter to set ceph rbd imageformat. Ceph rbd imageformat can only be 1 or 2, set the default value to 1.

**Release note**:
```release-note
Allow StorageClass Ceph RBD to specify image format and image features.
```