Add tetherApplyDnsInterfaces() binder interface.

Bug: 9580643
Change-Id: I781a422c969deb153bc8370edda4578612af6dc6
diff --git a/server/TetherController.h b/server/TetherController.h
index 6035c25..3769890 100644
--- a/server/TetherController.h
+++ b/server/TetherController.h
@@ -54,9 +54,9 @@
     int tetherInterface(const char *interface);
     int untetherInterface(const char *interface);
     const std::list<std::string> &getTetheredInterfaceList() const;
+    bool applyDnsInterfaces();
 
 private:
-    bool applyDnsInterfaces();
     bool setIpFwdEnabled();
 };