iptables_bpf_dns.py: mention ipv4 in generated script name
iptables_bpf_dns.py: mention ipv4 in generated script name

nivertech/bpftools,nivertech/bpftools,cloudflare/bpftools,mynameiscfed/bpftools,GeoffreyPlouviez/bpftools,mynameiscfed/bpftools,cloudflare/bpftools,GeoffreyPlouviez/bpftools