Fix tests

[wvengen]

After the last bundle update tests are failing.
https://travis-ci.org/foodcoops/foodsoft/builds/106242310

[wvengen]

huacnlee/rails-settings-cached#73 is the cause of failing config test

[wvengen]

the other problem was a capybara upgrade, where some buttons fall off the page now and can't be found anymore. Worked around by scrolling the page to the bottom in d6bf09b

[wvengen]

Still a problem though :(

[wvengen]

Tests succeed locally, so it's a Travis problem now ...

[wvengen]

Yay, needed to start a display manager so that the browser window could be maximised. After updates of capybara/selenium/firefox, it seemed that the browser window got a slightly different size, not enough for all tests to have the relevant elements in view.

Fixed by 6d338ff.