Bug#779578: user-setup: Please install sudo when installing without root password

[Teemu Ikonen <tpikonen@gmail.com>]

Package: user-setup
Severity: normal
Tags: d-i

I installed jessie from the daily netinst image and did not enter a
password for root. The end result was a working system without root
access as sudo was not installed.

The installer should make sure that sudo is installed, when the root
password is left empty.

I was installing on a hard-drive with /etc and /home from a previous
jessie install. The installer should also add the user created during
root-passwordless installation to the group 'sudo', but since my previous
install already had this, I do not know if this is made on fresh
install.

-- System Information:
Debian Release: 8.0
  APT prefers testing-updates
  APT policy: (500, 'testing-updates'), (500, 'testing')
Architecture: i386 (i686)

Kernel: Linux 3.16.0-4-686-pae (SMP w/2 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)