[CBM] Restore with map-data failing when bucket deleted and recreated

Issue:
Restoring data where the bucket is deleted and recreated and then mapped to another bucket fails.

Steps to reproduce:
1. Configure a backup repo
2. Create bucket "B0" and load some data
3. Do a backup
4. Delete "B0"
5. Create bucket with name "B0" again and load some data
6. Do a backup
7. Create bucket "new_bucket"
7. Do a restore with --map-data B0=new_bucket

This gives error:

Error restoring cluster: invalid mapping 'B0=new_bucket', source does not exist

Expected
For the data in the last backup to be restored to new_bucket