Allow disk attachment to diskless instances
Allow disk attachment to diskless instances

As only DRBD disks can be associated to more nodes than the instance
where we want to attach the disk to, we have to change the check for
associated nodes, too.

Signed-off-by: Lisa Velden <f95ae155456787aef400a49db463a62bbef84ead@google.com>
Reviewed-by: Oleg Ponomarev <c100474c6090841e9d55cde74d38d81efd269b8d@google.com>

andir/ganeti,yiannist/ganeti,ganeti/ganeti,onponomarev/ganeti,leshchevds/ganeti,leshchevds/ganeti,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,ganeti/ganeti,mbakke/ganeti,andir/ganeti,yiannist/ganeti,onponomarev/ganeti,andir/ganeti,mbakke/ganeti,yiannist/ganeti