QAPISchema._make_features() takes a definition expression, and extracts its 'features' member. The other ._make_FOO() leave destructuring expressions to their callers. Change ._make_features() to match them. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200317115459.31821-17-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>