update tests to expect success for all 2.7.15 builds
update tests to expect success for all 2.7.15 builds

Scalingo/python-buildpack,benmurden/heroku-buildpack-python-ember,ad-m/heroku-buildpack-python,benjaminfox/heroku-buildpack-python-geoip,benmurden/heroku-buildpack-python-ember,benjaminfox/heroku-buildpack-python-geoip,heroku/heroku-buildpack-python,heroku/heroku-buildpack-python,AltSchool/heroku-buildpack-python,Scalingo/python-buildpack,skilljar/heroku-buildpack-python,ad-m/heroku-buildpack-python,AltSchool/heroku-buildpack-python