support block volume

[rootfs]

this is cherry picked from #97, removing csi v1 commits

[rootfs]

ping @mkimuram

[mkimuram]

@rootfs

Thank you for your help in making block-volume-feature PR progress.
It looks good except that there are three lines missing in csi-rbdplugin.yaml.
After adding them, it worked properly in my environment.

# diff -urN csi-rbdplugin.yaml.orig csi-rbdplugin.yaml
--- csi-rbdplugin.yaml.orig     2019-01-16 20:12:59.877833851 +0000
+++ csi-rbdplugin.yaml  2019-01-16 20:21:36.182023115 +0000
@@ -69,6 +69,9 @@
           volumeMounts:
             - name: plugin-dir
               mountPath: /var/lib/kubelet/plugins_registry/csi-rbdplugin
+            - name: plugin-mount-dir
+              mountPath: /var/lib/kubelet/plugins/kubernetes.io/csi/volumeDevices/
+              mountPropagation: "Bidirectional"
             - name: pods-mount-dir
               mountPath: /var/lib/kubelet/pods
               mountPropagation: "Bidirectional"

[rootfs]

thanks @mkimuram

[rootfs]

Tested on k8s 1.13.2 with CSIBlockVolume gate enabled.