Some files are not properly synched in /etc when performing an update

[matbme]

Files like /etc/abroot/packages.* are not synced when performing an update or apply operation.

My suspicion is that line 577 in core/system.go (currently newEtc := filepath.Join(systemNew, "/etc") ) needs to be replaced with newEtc := filepath.Join(systemNew, "/.system/etc"), since the new root's /etc is an overlay mount combining /.system/etc and /var/lib/abroot/etc/[root-label].