Modernise code to use override specifier

Generated by clang-tidy.

Test: m checkbuild
Change-Id: I8e23da6b8af31b291be2eefe9937ca222ea8a8c3
diff --git a/tools/versioner/src/Driver.cpp b/tools/versioner/src/Driver.cpp
index 6062240..3927480 100644
--- a/tools/versioner/src/Driver.cpp
+++ b/tools/versioner/src/Driver.cpp
@@ -62,7 +62,7 @@
       : header_database(header_database), type(type) {
   }
 
-  virtual void HandleTranslationUnit(ASTContext& ctx) override {
+  void HandleTranslationUnit(ASTContext& ctx) override {
     header_database->parseAST(type, ctx);
   }
 };