Comment 2 for bug 1989807

Apparently rm_conffile is considerably more stubborn than I'd given it credit for, when it comes to removing files previously unowned by packages (i.e. /etc/cloud/cloud.cfg.d/99-fake_cloud.cfg). The only successful method is to rm it in a postinst script unfortunately. The attached patch remedies this (along with the aforementioned fixes for LP: #1977764).