dlz_dlopen driver for bind9

[tridge at samba.org]

Hi Michael,

I forgot to mention that I ran across what looks like a bug in dlz
when I was writing the Samba dlz module.

In dns_sdlz_putrr() there is a check that the ttl of all records added
for the same name of the same type are the same:

		if (rdatalist->ttl != ttl)
			return (DNS_R_BADTTL);

I don't understand why this restriction is there. I hit this when I
had multiple A records for a name with different TTLs.

Is this just a sdlz bug, or is there something more subtle going on?

Cheers, Tridge