Rework the control flow of balloon_stats_get_all() to make it
easier for a later patch to split visit_end_struct(). Also
switch to the uint64 visitor to match the data type.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1454075341-13658-10-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>