Normally people shouldn't create temporary files on /, but if you're
running as root, why not?
Caught when running tst_qtemporaryfile as root:
openat(AT_FDCWD, "", O_RDWR|O_CLOEXEC|O_TMPFILE, 0600) = -1 ENOENT (No such file or directory)
Change-Id: Ibdc95e9af7bd456a94ecfffd1603ebfc17cea220
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: David Faure <david.faure@kdab.com>