smoketest: conntrack: T4691: lower test value for nf_conntrack_tcp_max_retrans
smoketest: conntrack: T4691: lower test value for nf_conntrack_tcp_max_retrans

The old value of 1024 is no longer supported by the most recent Kernel
vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x