[nonsystemd] NetworkManager, dbus and display managers require manual intervention

We have recently began a repackaging of [nonsystemd] packages (see #3290). The displaymanager-openrc package has been removed and specific init scripts have been added for their respective display manager (e.g. sddm-openrc for sddm, gdm-openrc for gdm and so on with lxdm, xdm and lightdm)

Regarding NetworkManager and dbus, their nonsystemd builds used to ship with their corresponding OpenRC init scripts, but now they were separated into networkmanager-openrc and dbus-openrc. Please install these when upgrading those packages.