Comment 1 for bug 1270025

For me it fails in a different way:
$ dot -Tpng ./Dokumente/computer/talks/efficient-bug-handling/bug-lifecycle.dot > /tmp/bug.png
Format: "png" not recognized. Use one of:

(sic - I didn't forget to copy&paste anything, it's really looking like that). Confirming that "dot -c" fixes that, this should indeed go into the postinst. I'll ask Matthias to confirm, and then upload that.