fix notes in ndb -> zone generation

Reference: /n/atom/patch/applied2013/tozonenit
Date: Fri Sep 27 17:20:43 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/ndb/tozone.c	Fri Sep 27 17:20:33 2013
+++ /sys/src/cmd/ndb/tozone.c	Fri Sep 27 17:20:33 2013
@@ -518,7 +518,7 @@
 domtoip(uchar *a, uchar *m, char *ip)
 {
 	char *p, *r, *s, buf[8];
-	int l, i, ip6, rem, bits, bits0, step, base, stop;
+	int l, i, ip6, rem, bits, bits0, step, base, stop, split;
 
 	memset(a, 0, IPaddrlen);
 	memset(m, 0, IPaddrlen);
@@ -528,11 +528,13 @@
 		step = 8;
 		base = 0;
 		stop = 96;
+		split = 8;
 	}else if (l >= 9 && cistrcmp(ip + l - 9, ".ip6.arpa") == 0){
 		ip6 = 1;
 		step = 4;
 		base = 0xf;
 		stop = 0;
+		split = 4;
 	}else
 		return -1;
 	bits = rem = 0;
@@ -579,8 +581,8 @@
 	}
 	if(ip6 == 0)
 		a[10] = a[11] = 0xff;
-	if(bits != stop - 8)
-		sysfatal("rev zone %s missing %d bits\n", ip, bits - stop + 8);
+	if(bits != stop - split)
+		print("rev zone %s missing %d bits\n", ip, bits - stop + split);
 	snprint(buf, sizeof buf, "/%d", bits0);
 	if(parseipmask(m, buf) == bits0)
 		sysfatal("parseipmask: %r");
@@ -673,7 +675,7 @@
 				if(strcmp(nt->val, dbfile) != 0){
 					p = ndbopen1(nt->val);
 					if(p == nil)
-						sysfatal("bad ndb file: %s\n", nt->val);
+						sysfatal("bad ndb file: %s", nt->val);
 					soas0(nt->val, p, r0, r1, f);
 					ndbclose(p);
 				}
@@ -797,7 +799,7 @@
 		sysfatal("Binit: %r");
 	db = ndbopen1(dbfile);
 	if(db == nil)
-		sysfatal("%s: no db files\n", argv0);
+		sysfatal("%s: no db files", argv0);
 	soas(dbfile, db, argv, argc);
 	ndbclose(db);
 	for(i = 0; i < soaidx; i++){