Add a socket mark parameter to tethering DNS commands.

This allows the framework to pass down to dnsmasq the socket mark
to use for DNS queries.

Bug: 16357676
Change-Id: I8933b6de198a92c2aaf0291931ace8966ddba275
diff --git a/server/ResponseCode.h b/server/ResponseCode.h
index c623acd..6a0c22c 100644
--- a/server/ResponseCode.h
+++ b/server/ResponseCode.h
@@ -29,6 +29,7 @@
     static const int TetherDnsFwdTgtListResult = 112;
     static const int TtyListResult             = 113;
     static const int TetheringStatsListResult  = 114;
+    static const int TetherDnsFwdNetIdResult   = 115;
 
     // 200 series - Requested action has been successfully completed
     static const int CommandOkay               = 200;