Make setup.py python 2 friendly (#46317)
Summary:
import print_function to make setup.py invoked by Python2 print human readable error:
```
% python2 setup.py
Python 2 has reached end-of-life and is no longer supported by PyTorch.
```
Also, remove `future` from the list of the PyTorch package install dependencies
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46317
Reviewed By: walterddr, bugra
Differential Revision: D24305004
Pulled By: malfet
fbshipit-source-id: 9181186170562384dd2c0e6a8ff0b1e93508f221
