Fix the install of TensorBoard for doc generation (#19814)
Summary:
One more fix for https://github.com/pytorch/pytorch/pull/19810
We now know that we are running with python3, so no need to check python version. The quotes were probably causing problems here.
cc ezyang soumith zou3519
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19814
Differential Revision: D15106459
Pulled By: orionr
fbshipit-source-id: 0443b9b54d17fead9c8c2c9d8d2f373e1f95a28b
