update setup_helpers and a corresponding setup.py change

This updates setup_helpers to the latest version to allow @astrofrog to finish up #3166 .

@embray - was it intentional to require this modification to ``setup.py``?  Or did you not realize that `is_distutils_display_option` is also used in setup?  An alternative to this PR is to put `is_distutils_display_option` back into `setup_helpers` in the `setup_helpers` package.

See related discussions in astropy/astropy-helpers#110 and #3166