For some (yet) unknown reason extern-device-migrate is called
twice, once with a missing domname argument.
The following invocation loops forever:
external-device-migrate -domname
because "shift 2" never shifts ($# < 2) and $# is always 1.
From: Pascal Bouchareine <pascal@gandi.net>
Signed-off-by: Keir Fraser <keir@xensource.com>