[C++11] Remove an LLVM_OVERRIDE use that I missed in my previous commit.

llvm-svn: 202630

clang/lib/ASTMatchers/Dynamic/Marshallers.h

@@ -637,7 +637,7 @@ public:
       *LeastDerivedKind = Kind;
     return true;
   }
-  bool isPolymorphic() const LLVM_OVERRIDE { return true; }
+  bool isPolymorphic() const override { return true; }
 
 private:
   const unsigned MinCount;