Do not delete ClusterRemove or ClusterData
Do not delete ClusterRemove or ClusterData

Instead of deleting them, have ClusterRemove and ClusterData
be composed of exported and non-exported interfaces for compatability
with Portworx code.

Signed-off-by: Luis Pabón <faea5242a00c52da62a0f00df168c199b7ab748d@portworx.com>

pault84/openstorage,libopenstorage/openstorage,libopenstorage/openstorage,pault84/openstorage,libopenstorage/openstorage,pault84/openstorage