shill: Add C++11 override specifier to destructors of derived classes.

BUG=None
TEST=`USE=wimax FEATURES=test emerge-$BOARD platform2`

Change-Id: I88d4e29165869b26924cccb94ac940dc8961c312
Reviewed-on: https://chromium-review.googlesource.com/212267
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
diff --git a/default_profile.h b/default_profile.h
index afae425..fa84327 100644
--- a/default_profile.h
+++ b/default_profile.h
@@ -34,7 +34,7 @@
                  const base::FilePath &storage_path,
                  const std::string &profile_id,
                  const Manager::Properties &manager_props);
-  virtual ~DefaultProfile();
+  ~DefaultProfile() override;
 
   // Loads global configuration into manager properties.  This should
   // only be called by the Manager.