When object count is bigger than 1000, IsTruncated is True, then
the restore will fail. (Although object number of the cinder mode
backup of a volume will never be bigger than 1000 with using
multipart upload in s3 driver, this should also be fixed)
Depends-On: I7586763cf25be7ca115c7325129a7c9aa7022603
Change-Id: I9e972023817f3c804ae02e925b93811e1e05cc52