Build broken after German translation merge

[amercader]

After merging of https://github.com/okfn/opendataday/pull/256 the site no longer builds, eg https://travis-ci.org/okfn/opendataday/builds/636771935

Started build
U de/index.html
U de_at/index.html
  E de_at/index.html (UndefinedError: 'None' has no attribute 'items')
U index.html
U es_es/index.html
U fr/index.html
U it/index.html
U ja/index.html
U ne/index.html
U nl/index.html
U pt_br/index.html
U ru/index.html
U zh_tw/index.html
U de/style-guide/index.html
U de_at/style-guide/index.html
  E de_at/style-guide/index.html (TypeError: expected string or buffer)
U style-guide/index.html
U es_es/style-guide/index.html
U fr/style-guide/index.html
U it/style-guide/index.html
U ja/style-guide/index.html
U ne/style-guide/index.html
U nl/style-guide/index.html
U pt_br/style-guide/index.html
U ru/style-guide/index.html
U zh_tw/style-guide/index.html
U js/plugins.js
U js/main.js
U js/map.js
U css/style.css.map
U css/style.css
U css/main.css
U images/banner.png
U images/banner_2x.png
U scss/main.scss
U icons/money.svg
U icons/code-outline.svg
U icons/sparc.svg
U icons/card.svg
U icons/hewlett.svg
U icons/hivos.svg
U icons/user-outline.svg
U icons/fco.svg
U icons/brush.svg
U icons/book.svg
U icons/chart-bar.svg
U icons/environment.svg
U icons/ilda.svg
U icons/equality.svg
U icons/mapping.svg
U icons/environment2.svg
U icons/ocp.svg
U icons/datopian.svg
U icons/mapbox.svg
U icons/down.svg
U icons/frictionless.svg
U icons/rights.svg
U icons/research.svg
Error: Build failed with 2 failures.

Either we improve the logic used to render the translations to support this case or we revert the change.

cc @loleg @StephenAbbott @lwinfree

[StephenAbbott]

@amercader Thanks for this, Adria. Can you please revert?

[amercader]

Done. @loleg feel free to resubmit with changes to ensure that the Travis build is green