There were a couple of functions which were unused:
ensure_nbd, map_nbd, unmount_qcow_image, mount_qcow_image, ensure_sudo
Because some of them use 'trap ... EXIT' this hinders introducing a
separate exit phase - therefore they are removed.
(It would also be impossible to use them in the current setup, because
they overwrite the 'trap ... EXIT' of the disk-image-creates 'main'.)
Change-Id: If932a557dca9aea4864154ad6c4f286373d6dd7c
Signed-off-by: Andreas Florath <andreas@florath.net>
b365d3c833