Add netd binds for clearing DNS interface maps

Add resolver clearifacemapping to clear both the uidrange => interface DNS map
and the pid => interface DNS map

Change-Id: I144f4d092780b532633d8a956f68a6888d46797a
diff --git a/ResolverController.h b/ResolverController.h
index 51b449f..e705c8f 100644
--- a/ResolverController.h
+++ b/ResolverController.h
@@ -35,6 +35,7 @@
     int clearDnsInterfaceForPid(int pid);
     int setDnsInterfaceForUidRange(const char* iface, int uid_start, int uid_end);
     int clearDnsInterfaceForUidRange(int uid_start, int uid_end);
+    int clearDnsInterfaceMappings();
 };
 
 #endif /* _RESOLVER_CONTROLLER_H_ */