The device's guest interface and its QEMU user interface are
flawed^Whotly debated.  We'll resolve that in the next development
cycle, probably by deprecating the device in favour of a cleaned up,
but not quite compatible revision.

To avoid adding more baggage to the soon-to-be-deprecated interface,
mark property "memdev" as experimental, by renaming it to "x-memdev".
It's the only recent user interface change.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1448384789-14830-6-git-send-email-armbru@redhat.com>
[Update of qemu-doc.texi squashed in]
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>