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>
parse_DEC_MPLS_TTL(char *arg OVS_UNUSED, struct ofpbuf *ofpacts,
                   enum ofputil_protocol *usable_protocols OVS_UNUSED)
{
    ofpact_put_DEC_MPLS_TTL(ofpacts);
    return NULL;
}

parse_DEC_MPLS_TTL(char *arg OVS_UNUSED, struct ofpbuf *ofpacts,
                   enum ofputil_protocol *usable_protocols OVS_UNUSED)
{
    ofpact_put_DEC_MPLS_TTL(ofpacts);
    return NULL;
}
