Bug#897364: [debian-installer] debian-installer: fails to install to unclean target (tar: can't open ?)

[kardan <kardan@riseup.net>]

Package: debian-installer
Severity: normal

--- Please enter the report below this line. ---

Installing debian stretch onto an unclean target fails with

tar: can't open './lib/x86_64-linux-gnu/libacl.so.1.1.0': File exists

Instead existing files should be overwritten or kept instead of
failing. The install script should check for tar's error code and
continue silently if the file exists.

Installer source:
http://ftp.nl.debian.org/debian/dists/stretch/main/installer-amd64/current/images/netboot/mini.iso              
http://ftp.nl.debian.org/debian/dists/stretch/main/installer-amd64/current/images/netboot/netboot.tar.gz        
http://ftp.nl.debian.org/debian/dists/stretch/main/installer-amd64/current/images/netboot/pxelinux.0
(ctime: Mar  4 20:38)

Thanks for your great work!