CA-124991: Produce v1 RRDs for I/O errors and next VHD block

Signed-off-by: Jon Ludlam <jonathan.ludlam@eu.citrix.com>
Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Vineeth Thampi Raveendran <vineeth.thampi@citrix.com>

GitHub: closes #66 on xapi-project/blktap