Do not copy tests into /var/lib/utah/testsuites/, use a temp dir

To work around this, I did "sudo chmod -R g+ws /var/lib/utah/". However, that seems bad -- why does utah insist on copying the whole test and logs to /var/lib/utah? If you run a local file, everything is already there, and if you fetch stuff, I recommend to rather use a temporary dir than piling up all the bits in the utah user's home directory?

I certainly won't be against using temporary directories instead of using /var/lib/utah/testsuites.

Joe, what do you think about this? Why the design requires to have the test cases in a fixed location?

To elaborate on this: Without the setgid, running tests as different user (e. g. "ubuntu" in a live system or "martin" on my local workstation) is impossible; but I can't run desktop tests as "utah" user as that user does not have a running desktop session. With the setgid, running tests as different users is highly insecure, because anyone in the utah group can basically provide arbitrary code which then gets executed by other users.

I recommend to use temp dirs for anything you need to download, and the usual XDG dirs (in particular $HOME/.cache) for log files and the like. Then "utah -r" will work for the "utah" user just as well as for any other user.

If this means a temp dir on a temporary filesystem, this will break reboot support. If we can create a temp dir that persists across reboots, we could make that work.

That being said, I think supporting running as different users is causing us more problems than the benefits we're getting from it, but that's mostly on the server side. I think we should discuss the need for continued support for users other than root and utah at some point.