Change: Do not display outline when the files list is focused

The files list was displaying outline when it received focus after a click.
Since the focus is meant only programmatically, the outline was not supposed to be displayed.

https://github.com/owncloud/web/issues/3747
https://github.com/owncloud/web/issues/3551
https://github.com/owncloud/web/pull/3752
