Bug#295111: tasksel: Manual package selection does not allow manual package selection (revisited)

[Frans Pop <aragorn@tiscali.nl>]

Package: tasksel
Version: 2.22
Severity: important
Tags: d-i

Sorry for reporting this so late. I started testing this several times,
but ran into a snag each time. Today, finally I got around to it.
Follow-up for (archived) bug #272360.

If tasksel is run from base-config and I select no tasks, tasksel will
still run with the --visual-preview parameter.

If I run tasksel from the commandline, it works as expected:
- if I select an extra task, aptitude is run with --visual-preview;
- if I don't select an extra task, aptitude is run without --visual-preview;

-- System Information:
Debian Release: 3.1
  APT prefers testing
  APT policy: (990, 'testing')
Architecture: i386 (i686)
Kernel: Linux 2.6.8-13.0501-1
Locale: LANG=en_US, LC_CTYPE=en_US (charmap=ISO-8859-1)

Versions of packages tasksel depends on:
ii  aptitude                      0.2.15.8-1 terminal-based apt frontend
ii  debconf [debconf-2.0]         1.4.30.11  Debian configuration management sy
ii  liblocale-gettext-perl        1.01-17    Using libc functions for internati