ofp-actions: Avoid buffer overread in BUNDLE action decoding.

Reported-at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=9052
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Justin Pettit <jpettit@ovn.org>
format_PUSH_VLAN(const struct ofpact_null *a OVS_UNUSED, struct ds *s)
{
    /* XXX 802.1AD case*/
    ds_put_format(s, "%spush_vlan:%s%#"PRIx16,
                  colors.param, colors.end, ETH_TYPE_VLAN_8021Q);
}

format_PUSH_VLAN(const struct ofpact_null *a OVS_UNUSED, struct ds *s)
{
    /* XXX 802.1AD case*/
    ds_put_format(s, "%spush_vlan:%s%#"PRIx16,
                  colors.param, colors.end, ETH_TYPE_VLAN_8021Q);
}
