Print title of step when it fails

[hadess]

When one of the buildbot steps fails, the only thing we see in the logs is the command itself, which isn't very helpful in diagnosing the problem for packagers to solve.

But the steps have names associated, which should be printed when the step fails. Then, the names could be expanded so they hint at the exact failure cause. Eg.

Check for right id in AppStream xml could be Check that desktop file id matches Flatpak ID org.gnome.Test