Bugfix: Contextmenu button triggered wrong event 

The contextmenu button in the OcTableFiles triggered a `showDetails` event, which 
lead to the sidebar appearing instead of the (expected) contextmenu. This has been fixed.

https://github.com/owncloud/owncloud-design-system/pull/1610
https://github.com/owncloud/owncloud-design-system/issues/1608
