This should complete all combinations that make sense WRT
default /etc/network/interfaces handling

Network interfaces in VM should listen to DHCP by default,
and if /etc/network/interfaces doesn't exist at all (so
takeover from host to guest isn't possible either) create
a sane default as well.

Thanks: Christian Hofstaedtler <christian@hofstaedtler.name> for suggestion + review
Thanks: Ulrich Dangel <mru@spamt.net> for review
Fixes #20

As needed in a $customer environment (not to be named [yet]).

Thanks: Michael Renner <michael.renner@amd.co.at> for feature request and sponsoring my development time

Thanks: Michael Renner <michael.renner@amd.co.at> for initial bug report and sponsoring my development time

This effectively executes grml-debootstrap under 'set -x'
(including the chroot script), so it's easy to generate an
execution log via e.g.:

  grml-debootstrap ... --debug --force 2>&1 | tee -a grml-deboootstrap.log

and providing it to grml-debootstrap developers for further
investigation.

It should be safe to default to ext4 nowadays with Debian/wheezy
being the stable Debian release.

mount.smbfs is apparently gone, and mount.cifs doesn't understand "defaults" any more.

Noticed via recent libssl1.0.0 upgrade that the
DEBIAN_FRONTEND usage is missing in the $APTUPGRADE
command line.

Credit goes got Thorsten Staerk for his help on stackexchange.
(https://unix.stackexchange.com/questions/111414/how-to-change-the-disk-signature-of-a-raw-image)

added $DPKG_OPTIONS to all instances of apt-get and aptitude (attempt 2) https://github.com/grml/grml-debootstrap/issues/8

Set absolute path to /usr/sbin/update-locale to make sure
the binary can be accessed no matter what's inside $PATH
and if it's not present inform user about it, but do not fail
because the locales-all package might be installed and it doesn't
provide the /usr/sbin/update-locale binary.

Since the "qemu-img create" always uses "raw" format, clarify that.

While at it adjust order of CHROOT_SCRIPTS, PRE_SCRIPTS and
CHROOT_SCRIPTS to better fit the actual execution order.

Thanks: Jimmy Gredler for the hint

It's just too annoying to install a system which depends on
vlan configuration and not being able to access the network then.

Inspired by https://github.com/grml/grml-debootstrap/pull/10,
thanks adrelanos

Installing boot loader just on the first disk seems to cause
problems recently, looks like at least Debian/wheezy's grub
properly supports installation on /dev/md# devices, so let's try
that route instead...

Defaults to en_US.UTF-8