RNN operators should inherit step_net device_options (#16086)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16086
[caffe2] RNN operators should inherit step_net device_options
According to NetDef documentaiton, if network has a specific device option it applies to all network operators that do not explicitly specifiy it.
But this does not seem to be the case for RecurrentNetwork operators
Reviewed By: orionr
Differential Revision: D13699552
fbshipit-source-id: 14529bc9504e3b02f763e3c2429be21e46f82b68
