If you're on vCenter 6.5, there is no longer the need for any Client Integration Plugin for uploading files to datastores. And the Enhanced Authentication Plugin is only for Windows because that's where it's only relevant, for AD single sign-on. If you haven't tried already the HTML5 client, which both comes prepackaged into vCenter 6.5b and forward, as well as updated weekly as a fling, you might want to check that out as its HTML5 allows you to upload files plug-in free. This has worked perfectly for me on Ubuntu in the past.
