atlas_install_python_modules: fix POST_BUILD_CMD
!802 (merged) broke running of flake8 in atlas_install_python_modules
. Use the
correct target for triggering the checking.
This one is rather urgent as we are currently not running any flake8
checking in master
@akraszna, the MR into athena will certainly require a few extra python fixes to go along with it. I can provide those and push them into the MR once you have opened it.