Description of problem:

If a stale snapshot exists while using data mover, the backup will partially fail, whereas it should instead complete with a warning.

How reproducible:

100%

Steps to Reproduce:
1. Create a volumesnapshot in app ns with a backup label different from the actual backup name.
2. Take backup using data mover.

Actual results:

Backup will partially fail.

Expected results:

Backup completes with a warning.