Comment 8 for bug 1828118

Namely partial/ is an _apt owned sandbox arena. I think there is some code to restore a missing one and fixup permissions but that's super ugly.

The correct change to make for cleaning apt would be to run apt-get clean with -o dir::etc::sourcelist=/dev/null, same with sourceparts.

That will take care of cleaning everything up that should be cleaned up and stop messing with internals.