hw/xen_disk: aio_inflight not released in handling ioreq when nr_segments==0

In hw/xen_disk.c, async writing ioreq is leaked when
ioreq->req.nr_segments==0, because `aio_inflight` flag is not released
properly (skipped by misplaced "break").

Signed-off-by: Feiran Zheng <famcool@gmail.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hw/xen_disk.c

diff --git a/hw/xen_disk.c b/hw/xen_disk.c
index ed9e5eb..445bf03 100644
--- a/hw/xen_disk.c
+++ b/hw/xen_disk.c
@@ -408,9 +408,9 @@
 	break;
     case BLKIF_OP_WRITE:
     case BLKIF_OP_WRITE_BARRIER:
-        ioreq->aio_inflight++;
         if (!ioreq->req.nr_segments)
             break;
+        ioreq->aio_inflight++;
         bdrv_aio_writev(blkdev->bs, ioreq->start / BLOCK_SIZE,
                         &ioreq->v, ioreq->v.size / BLOCK_SIZE,
                         qemu_aio_complete, ioreq);