Revert all changed lang docbooks, not only index.docbook

Review Request #7161 - Created May 15, 2016 and submitted - Latest diff uploaded

Burkhard Lück
trunk kf5

If checkXML5 fails for a new generated lang docbook, as of now only the changed index.dobook is reverted.

This is not sufficient for documentation whith more than one docbook.
In this case all changed lang docbooks have to be reverted.

This patch should be applied to all four branches processed by Scripty.

Test case:

Use update_xml without patch to generate the german docbbooks in application, only index.docbbok is reverted and lang de does not build anymore

With patch all changed german docbooks are reverted and lang de still builds