Bug#551838: debootstrap --unpack-tarball downloads Packages file.

[Bertram Felgenhauer <bertram.felgenhauer@googlemail.com>]

Package: debootstrap
Version: 1.0.27

When running debootstrap --unpack-tarball using a tarball created
with the --make-tarball, the Packages file is downloaded again,
despite being included in the tarball.

This is bad for two reasons:
 1) there may be no network connection in that second run of debootstrap
 2) the new Packages file may be inconsistent with the packages
    downloaded earlier, pretty much defeating the purpose of creating
    the tarball in the first place.

The behaviour is strongly related to #551838. In fact this is a
feature (the Packages file is downloaded using the 'nocache' option
in /usr/share/debootstrap/functions).

For the original reporter, this was surprising and annoying, and I tend
to agree with him.

But even if the feature is there to stay, I think that this behaviour
should be disabled by --make-tarball.

Best regards,

Bertram Felgenhauer