Description of problem:
Changing the default StorageClass to one that supports snapshots, without deleting initial PVCs, eventually causes DataSources to become non-ready.

Version-Release number of selected component (if applicable):
4.14.0

How reproducible:
100%

Steps to Reproduce:
1. Deploy w/ hostpath-csi-basic default StorageClass
2. Alter default StorageClass to snapshot supported SC (ocs-storagecluster-ceph-rbd)
3. Wait for reconciliation to update DataSource to snapshot

Actual results:
DataSource source changed to snapshot, but shows not-ready because original PVC source still exists.

Expected results:
DataSource does not change from PVC source to Snapshot source until original PVC source deleted.

• or -
  Original PVC converted to snapshot

Additional info:
W/A: Delete PVC source to recreate for snapshot

• or -
  Revert default StorageClass and update DataSource(s) manually to use original PVC