Enable fairseq fblearner sweep backend to use manifold for checkpoint savings
Enable fairseq fblearner sweep backend to use manifold for checkpoint savings

Summary: Deffault fairseq fblearner sweep backend uses gluser to save checkoints which is slow for large models. This diff enables fairseq fblearner sweep to use manifold for checkpoint savings.

Reviewed By: akinh

Differential Revision: D22770343

fbshipit-source-id: ec5174e490c35f2c7d11ccf69f3b6e9adcd8ac7b

pytorch/fairseq,pytorch/fairseq,pytorch/fairseq