Bug#557296: debootstrap: Use dpkg-deb instead of ar when available

[Frans Pop <elendil@planet.nl>]

On Saturday 21 November 2009, Otavio Salvador wrote:
> In my opinion debootstrap shouldn't work differently inside of Debian
> so I think we shouldn't use dpkg-deb for this. Even though it would
> make our life easier giving us "new features" for free it also makes
> much more difficult to spot possible missing features when using it in
> foreign distributions and I believe this is something we ought to
> support well.

That was my initial reaction as well. One thing that could count against 
that is that in Debian Installer dpkg-deb is not available either, which 
would probably ensure sufficient testing of that path.

I should IMO be agreed that debootstrap should never rely on features not 
commonly available using basic *nix tools.