virtio-blk: add acct_failed param to virtio_blk_handle_rw_error()

We add acct_failed param in order to use virtio_blk_handle_rw_error()
also when is not required to call block_acct_failed(). (eg. a discard
operation is failed)

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20190221103314.58500-2-sgarzare@redhat.com
Message-Id: <20190221103314.58500-2-sgarzare@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>