Remove unneeded env variables.
Remove unneeded env variables.

* `DISPLAY` isn't needed since we switched from capybara-webkit to phantomjs
* Nothing in the app should depend on `FACTER_*` variables.
telekomatrix/publisher,alphagov/publisher,alphagov/publisher,leftees/publisher,telekomatrix/publisher,leftees/publisher,telekomatrix/publisher,telekomatrix/publisher,alphagov/publisher,leftees/publisher,leftees/publisher