[PATCH for-5.0] xen-block: Fix uninitialized variable

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

Since 7f5d9b206d1e ("object-add: don't create return value if
failed"), qmp_object_add() don't write any value in 'ret_data', thus
has random data. Then qobject_unref() fails and abort().

Fix by initialising 'ret_data' properly.

Fixes: 5f07c4d60d09 ("qapi: Flatten object-add")
Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 hw/block/xen-block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index 07bb32e22b51..99cb4c67cb09 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -860,7 +860,7 @@ static XenBlockIOThread *xen_block_iothread_create(const 
char *id,
     XenBlockIOThread *iothread = g_new(XenBlockIOThread, 1);
     Error *local_err = NULL;
     QDict *opts;
-    QObject *ret_data;
+    QObject *ret_data = NULL;
 
     iothread->id = g_strdup(id);
 
-- 
Anthony PERARD