Tests: properly report test results, fix sandboxing

Originall pull request https://github.com/nemomobile-packages/qtmozembed/pull/6
My reasoning was simply that that it was commented out because of the dependency of dbus-launch on x11 which was removed already some time ago - this allowed to uncomment it again. I had no clue if it was really needed to launch separate dbus session but if the original author thought so, ...