Failed to restore if file name duplicate

[YK-Samgo]

If one domain has two qcow2 file share the same name in different folder, backup will be successful but restore may fail.

For example, domain test has 2 qcow2 file, vda in /mnt/a/data.qcow2 and vdb in /mnt/b/data.qcow2. Backup was successful, but I met problem when restore it. The restore tried to put the 2 data.qcow2 into the same target_dir, which threw a qcow2 file already exists error.

[aruhier]

Thanks for the bug report, I'll try this scenario. Do you use zstd or tar or do you use directory? https://virt-backup.readthedocs.io/en/latest/config.html#packagers