The group display is obviously a system group that should exist.
Its gid MUST be between 100 and 499. It was previously created
byweston-common project (and it is still created by this package
if not already existing).
Change-Id: I7a98ed5b7d1780092ea45e47aa7651154d02ee41 Signed-off-by: José Bollo <jose.bollo@open.eurogiciel.org>