Automatic merge from submit-queue
Make Constants Public so that They Can Be Used in an Ext. Provisioner
Out-of-tree external provisioners have the same purpose as in-tree provisioners. As external provisioners work with PV and PVC datastructures it's an advantage to import certain Kubernetes packages instead of copy-pasting the Kubernetes code.
That's why the constants are made public so that they can be used in an external provisioner.
@jsafrane @kubernetes/sig-storage-pr-reviews
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NONE
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