Revert "Fix: failing unit test (DocumentationViewerTest)"
Revert "Fix: failing unit test (DocumentationViewerTest)"

This reverts commit aacc16c9793c7047cb154d1e553add2eb32a0d3c.
This fix was based  on using docsviewer with framework 3.1-dev and
fails on 3.0.3 stable

camfindlay/silverstripe-docsviewer,camfindlay/silverstripe-docsviewer,silverstripe/silverstripe-docsviewer,silverstripe/silverstripe-docsviewer,dhensby/silverstripe-docsviewer,dhensby/silverstripe-docsviewer