Without this stub, the next commit fails to link. I suspect the real
cause is 947e47448d "monitor: Use getter/setter functions for
cur_mon".
Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210318155519.1224118-9-armbru@redhat.com>