fix check_updates to work with just buildtype

arch was not retrieved correctly

Signed-off-by: Manuel Traut <manut@linutronix.de>
examples: Exchange debian.tu-bs.de with ftp.de.debian.org
add empty tag for ubi volumes

is useful to create empty ubivolumes with a name that was used in the fstab

Signed-off-by: Manuel Traut <manut@linutronix.de>
unset DEBCONF_REDIR in preseed

the installer uses DEBCONF_REDIR to tell debconf scripts, that the
fd 3 is connected to the stdout.
But in preseed.sh this fd seems to be closed already.
This made apt-get install fail.

Unsetting it, mitigates the problem.

Signed-off-by: Torben Hohn <torbenh@linutronix.de>
copy all ubi volumes out of the buildenv

Signed-off-by: Manuel Traut <manut@linutronix.de>
support multiple ubi volume groups in one or more mtd partitions

Signed-off-by: Manuel Traut <manut@linutronix.de>
add a second ubi volume group / mtd device to the arm-complex-example

Signed-off-by: Manuel Traut <manut@linutronix.de>
make ubinize command better readable

Signed-off-by: Manuel Traut <manut@linutronix.de>
add DEBCONF_REDIR= to all apt-get install calls

Signed-off-by: Manuel Traut <manut@linutronix.de>
add DEBCONF_REDIR= to apt-get install call in mkcdrom

Signed-off-by: Manuel Traut <manut@linutronix.de>
add DEBCONF_REDIR env var to apt-get install

this fixes the installation of packages specified in <buildenv><pkg-list>
and avoids a deadlock in the preseeding step

Signed-off-by: Manuel Traut <manut@linutronix.de>