qemu-iotests: fix 051.out after qdev error message change

Commit f006cf7f ("qdev-monitor:
Propagate errors through qdev_device_add()") dropped a meaningless error
message.  This change in output caused qemu-iotests 051 to fail:

   QEMU_PROG: -device ide-drive,drive=disk: Device initialization failed.
  -QEMU_PROG: -device ide-drive,drive=disk: Device 'ide-drive' could not be initialized

Update 051.out so the test passes again.

Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1435071369-30936-1-git-send-email-stefanha@redhat.com