Pass dnsmasq the socket mark to use for listen sockets.

This allows us to configure dnsmasq to reply to DHCP requests and
DNS queries when a VPN is up.

Bug: 37778642
Test: bullhead builds and boots
Test: succesfully tethered when a VPN was connected
Change-Id: I7d5899f80fae856a52a2019550b155bccee2888a
diff --git a/server/TetherController.h b/server/TetherController.h
index 3769890..13da05c 100644
--- a/server/TetherController.h
+++ b/server/TetherController.h
@@ -23,6 +23,8 @@
 #include <set>
 #include <string>
 
+namespace android {
+namespace net {
 
 class TetherController {
 private:
@@ -60,4 +62,7 @@
     bool setIpFwdEnabled();
 };
 
+}  // namespace net
+}  // namespace android
+
 #endif