learning_rate cannot be set from conv1_w_lr

[dzung-hoang]

With a recent version of caffe2 from pytorch, I get the following error.

Traceback (most recent call last):
  File "mobile_net_trainer.py", line 475, in <module>
    main()
  File "mobile_net_trainer.py", line 468, in main
    Train(args)
  File "mobile_net_trainer.py", line 401, in Train
    explog
  File "mobile_net_trainer.py", line 162, in RunEpoch
    learning_rate = workspace.FetchBlob(prefix + '/conv1_w_lr')
  File "/usr/local/lib/python2.7/dist-packages/caffe2/python/workspace.py", line 339, in FetchBlob
    result = C.fetch_blob(StringifyBlobName(name))
RuntimeError: [enforce fail at pybind_state.cc:175] ws->HasBlob(name). Can't find blob: gpu_0/conv1_w_lr

I worked around this by removing the setting of learning_rate and the writing of it to the log.