change ip6.int to ip6.arpa, per the rfcs.
of course, nothing in ndb mangles ipv6 addresses into
the form needed for reverse lookups yet.

Reference: /n/sources/patch/applied/ipv6-rev-dns-domain
Date: Wed Jun 16 19:18:04 CES 2004

--- /sys/src/cmd/ndb/dblookup.c	Wed Jun 16 19:18:04 2004
+++ /sys/src/cmd/ndb/dblookup.c	Wed Jun 16 19:18:01 2004
@@ -862,7 +862,7 @@
 }
 
 char *v4ptrdom = ".in-addr.arpa";
-char *v6ptrdom = ".ip6.int";
+char *v6ptrdom = ".ip6.arpa";		/* ip6.int deprecated, rfc 3152 */
 
 char *attribs[] = {
 	"ipmask",