Fix compilation with Clang

Author: robertodr

src/utils/Symmetry.hpp

@@ -51,7 +51,7 @@ namespace utils {
  *    6  110   C2x     1.0
  *    7  111    i     -1.0
  */
-class Symmetry __final {
+class Symmetry final {
 public:
   Symmetry()
       : nrGenerators_(0),