net, net-dns: don't spam lo iface

features.in/net-dns/rootfs/image-scripts.d/60-net-dns

 #!/bin/sh
 # set default nameserver, if any
-for i in $GLOBAL_NAMESERVERS; do echo "nameserver $i"; done >> /etc/resolv.conf
+
+if [ $GLOBAL_NAMESERVERS = "example" ]; then
+	echo "# yandex"
+	echo "#nameserver 77.88.8.1"
+	echo "# google"
+	echo "#nameserver 8.8.8.8"
+	echo "# level3"
+	echo "#nameserver 4.2.2.1"
+	echo "#nameserver 4.2.2.2"
+	echo "#nameserver 4.2.2.3"
+else
+	for i in $GLOBAL_NAMESERVERS; do
+		echo "nameserver $i"
+	 done
+fi >> /etc/resolv.conf

features.in/net/rootfs/image-scripts.d/50-net-resolv

 #!/bin/sh
+# see also net-dns feature for actual nameserver control
 
-# offer some convenient servers for static configuration cases
-# (see also net-dns feature)
-if [ -d /etc/net/ifaces/lo ]; then
-	{
-	echo "# yandex"
-	echo "#nameserver 77.88.8.1"
-	echo "# google"
-	echo "#nameserver 8.8.8.8"
-	echo "# level3"
-	echo "#nameserver 4.2.2.1"
-	echo "#nameserver 4.2.2.2"
-	echo "#nameserver 4.2.2.3"
-	} >> /etc/net/ifaces/lo/resolv.conf
-fi
+# purge hasher-provided files potentially disclosing
+# build host's network configuration bits
 find /var -name resolv.conf -or -name nsswitch.conf -delete
 
 # hasher might have carried host /etc/hosts over, need to overwrite