[C++11] Add 'override' keyword to virtual methods that override their base class.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203344 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/ExecutionEngine.cpp

@@ -97,7 +97,7 @@ public:
     return static_cast<char*>(RawMemory) + sizeof(GVMemoryBlock);
   }
 
-  virtual void deleted() {
+  void deleted() override {
     // We allocated with operator new and with some extra memory hanging off the
     // end, so don't just delete this.  I'm not sure if this is actually
     // required.