unbound: fix SLAAC DNS inference

Bug: If DHCPv4 MAC are used to infer SLAAC and the forth position of
the subnet /64 is 0 (X:X:X:0::/64), then DNS records where malformed.

Signed-off-by: Eric Luehrsen <ericluehrsen@hotmail.com>

net/unbound/files/odhcpd.awk

@@ -94,7 +94,7 @@
             adr = ( adr slaac ) ;
 
 
-            if ( split( adr, tmp0, ":" ) >= 8 ) {
+            if ( split( adr, tmp0, ":" ) > 8 ) {
               sub( "::", ":", adr ) ;
             }