remove unused function from resnet50_trainer

Summary: Just noticed that I had duplicate code in the example imagenet trainer. Removed the function.

Differential Revision: D4223070

fbshipit-source-id: 443a9401bf7e425f7a3a13a44c9d0f7e21e72303
diff --git a/caffe2/python/examples/resnet50_trainer.py b/caffe2/python/examples/resnet50_trainer.py
index 58488b0..b7ab038 100644
--- a/caffe2/python/examples/resnet50_trainer.py
+++ b/caffe2/python/examples/resnet50_trainer.py
@@ -43,21 +43,6 @@
     data = model.StopGradient(data, data)
 
 
-def AddModel(args, train_model):
-    '''
-    Add the resnet-50 model operators.
-    '''
-    [softmax, loss] = resnet.create_resnet50(
-        train_model,
-        "data",
-        num_input_channels=args.num_channels,
-        num_labels=args.num_labels,
-        label="label",
-    )
-    train_model.Accuracy([softmax, "label"], "accuracy")
-    return loss
-
-
 def AddMomentumParameterUpdate(train_model, LR):
     '''
     Add the momentum-SGD update.