Merge pull request #4285 from aliang123/3486

blockdev_full_backup:add timeout in backup_options

Author: zhencliu

qemu/tests/cfg/blockdev_full_backup.cfg

@@ -65,7 +65,7 @@
                 - manual_completed:
                     auto-dismiss = false
                     auto-finalize = true
-            backup_options = "auto-dismiss auto-finalize compress sync"
+            backup_options = "auto-dismiss auto-finalize compress sync timeout"
 
         - during_reboot:
             type = blockdev_full_backup_reboot