migration: add_bitmaps_to_list: check disk name once

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200521220648.3255-6-vsementsov@virtuozzo.com>
[eblake: shorter subject line]
Signed-off-by: Eric Blake <eblake@redhat.com>
1 file changed