Bug fix for SQuAD example tuner. (#134)

examples/tuners/ga_customer_tuner/customer_tuner.py

@@ -61,7 +61,8 @@ class Individual(object):
 
     def mutation(self, config=None, info=None, save_dir=None):
         self.result = None
-        self.config = config
+        if config is not None:
+            self.config = config
         self.config.mutation()
         self.restore_dir = self.save_dir
         self.save_dir = save_dir
@@ -121,8 +122,7 @@ class CustomerTuner(Tuner):
         logger.debug(str(parameters))
         logger.debug(str(reward))
 
-        indiv = graph_loads(parameters)
-        indiv.result = reward
+        indiv = Individual(graph_loads(parameters), result=reward)
         self.population.append(indiv)
         return