netd: restrict DNS names

Do not accept WPAD or ISATAP from DHCP as names to public in DNS.

Change-Id: Ic88651bcf4b36205908e65fef41ea08cdca5e0b9
CRs-fixed: 2285921
diff --git a/server/TetherController.cpp b/server/TetherController.cpp
index 61ac8c5..c80ea80 100644
--- a/server/TetherController.cpp
+++ b/server/TetherController.cpp
@@ -217,6 +217,7 @@
             "/system/bin/dnsmasq",
             "--keep-in-foreground",
             "--no-resolv",
+            "--dhcp-ignore-names",
             "--no-poll",
             "--dhcp-authoritative",
             // TODO: pipe through metered status from ConnService