fix iso-image ls --quiet to show only image-ids

[ghostwheel42]

closes #134

[nvthongswansea]

In stead of if-else, you could do if-return. That would give a bit of performance, since it returns right away when the condition is met (instead of checking other conditions and then return at the end of the function).

[ghostwheel42]

Yes, I know. I’ve decided to stick to the if-else style already present in the existing code, even though this is not the normally used go style. I didn’t want to change too much of the existing code.

[nvthongswansea]

LGTM @bkircher any thoughts?

[bkircher]

Ja, looks good.

[bkircher]

Thanks @ghostwheel42 , @nvthongswansea!