listInstalled() reports packages in "config-files" (rc) state as installed

[brunodam]

Description

On Debian/Ubuntu systems, after running apt remove <pkg>, dpkg leaves the package in rc state (removed but config-files remain). Currently, listInstalled() still reports such packages as installed.

Example

apt install ebtables
apt remove ebtables
dpkg-query -W -f='${db:Status-Abbrev} ${Package}\n' ebtables
# => rc ebtables

Expected

• Packages in rc state should not be treated as installed by default.