updates of XTrainer

source/train/XTrainer.cpp

@@ -112,7 +112,7 @@ void XTrainer::Run(XConfig * config, DataDistributeBase * dataDistributor,
     leader.Start();
 
     /* train the model */
-    for (int epoch = 0; epoch < nepoch; epoch++) {
+    for (epoch = 0; epoch < nepoch; epoch++) {
 
         bool ok = true;
         dataDistributor->Start();