Pull Request #881 (https://github.com/opencast/opencast/pull/881) removes the `/modules/admin-ui/bower_components` folder from our `git` repository. Some files/subdirectories of that folder were previously ignore,ignored, though, which leads to the following annoying effect:
When you build Opencast from `develop`, `bower` will put all the dependencies back into `bower_components`, as it is supposed to. When you then check out, for example, `r/6.x` and switch back to `develop`, some of the files in `bower_components` remain, although they should all be deleted in `develop`.
This can break the build since `bower` will complain about preexisting subfolders of `bower_components` that it doesn't manage itself, as signified by a `.bower.json` file. This applies at least to `angular-wizard`.