dhcp_host_domain_ng.py ignores dhcp.@dnsmasq[0].leasefile setting

When I change dhcp.@dnsmasq[0].leasefile to point to /srv/dhcp.leases to get a persistent database, script dhcp_host_domain_ng.py still expects the default /tmp/dhcp.leases file.

This can be fixed by the following change to the end of the file (I could not fork the project, so I'm sending the fix here):

if __name__ == "__main__":
    leases = uci_get("dhcp.@dnsmasq[0].leasefile")
    if len(sys.argv) == 2 and sys.argv[1] == "ipv6":
        log("DHCPv6 leases not supported now", LOG_WARNING)
    elif len(sys.argv) > 4:
        log("DHCPv4 new lease", LOG_INFO)
        sys_op = sys.argv[1]
        mac = sys.argv[2]
        ipv4 = sys.argv[3]
        hostname = sys.argv[4]
        dd = DHCPv4(leases)
        dd.update_dhcp(sys_op, hostname, ipv4)
        dd.save_leases()
        dd.refresh_resolver()
    else:
        # get env variables in case of
        # call from dnsmasq dhcp-script.sh
        sys_op = os.environ.get('ACTION')
        mac = os.environ.get('MACADDR')
        ipv4 = os.environ.get('IPADDR')
        hostname = os.environ.get('HOSTNAME')
        dd = DHCPv4(leases)
        if sys_op and hostname and ipv4:
            dd.update_dhcp(sys_op, hostname, ipv4)
        dd.save_leases()
        dd.refresh_resolver()