Add specification of ms-dns arg to pppd.

This lets us tell the pc to use the tethered android as their dns server.

bug:2281900
diff --git a/PppController.h b/PppController.h
index 5046822..bb75435 100644
--- a/PppController.h
+++ b/PppController.h
@@ -32,7 +32,8 @@
     virtual ~PppController();
 
     int attachPppd(const char *tty, struct in_addr local,
-                   struct in_addr remote);
+                   struct in_addr remote, struct in_addr dns1,
+                   struct in_addr dns2);
     int detachPppd(const char *tty);
     TtyCollection *getTtyList();