clang-tidy: Enable modernize-use-override check

This check adds override (introduced in C++11) to overridden
virtual functions and removes virtual from those functions as it
is not required.

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I7ce6bf641dabf4d325a29a1b641e58beac6885bd
diff --git a/manager/group.hpp b/manager/group.hpp
index 014fea6..2c33445 100644
--- a/manager/group.hpp
+++ b/manager/group.hpp
@@ -24,7 +24,7 @@
 {
   public:
     Group() = delete;
-    ~Group() = default;
+    ~Group() override = default;
     Group(const Group&) = delete;
     Group& operator=(const Group&) = delete;
     Group(Group&&) = delete;