Fixed tar options and path for restoring images

`-z` option for tar is used to filter through gzip. This should be excluded for the restore as it was not used during the backup.
The path is also fixed as it recreated the entire path within the volumes folder.

Author: cherylq26

datacenter/dtr/2.4/guides/admin/backups-and-disaster-recovery.md

@@ -184,7 +184,7 @@ If you had DTR configured to store images on the local filesystem, you can
 extract your backup:
 
 ```none
-sudo tar -xzf {{ image_backup_file }} -C /var/lib/docker/volumes
+sudo tar -xf {{ image_backup_file }} -C /
 ```
 
 If you're using a different storage backend, follow the best practices