code improvements

components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/operation/mgt/dao/impl/GenericOperationDAOImpl.java

@@ -377,8 +377,7 @@ public class GenericOperationDAOImpl implements OperationDAO {
                             for (ActivityStatus status : activityStatuses) {
                                 if (deviceOpRes.getKey().equalsIgnoreCase(status.getDeviceIdentifier().getId())) {
                                     if (status.getResponses() == null) {
-                                        List<OperationResponse> responses = new ArrayList<>();
+                                        status.setResponses(new ArrayList<>());
-                                        status.setResponses(responses);
                                     }
                                     status.getResponses().addAll(deviceOpRes.getValue());
                                 }