tatt: incorrect load of use flags between profile and defaults

[arthurzam]

For sddm, we have IUSE="+elogind systemd test" when used in use-default mode.

pkgdev tatt -b 928073 --api-key $(</srv/tattoo/bugs.key) --use-default --template-file /srv/tattoo/pkgdev.tatt.template.sh

ebuild prefers elogind turned on, while profile puts it in reverse (systemd profile).