elements with invlid index.
	* grub-core/disk/mdraid_linux.c (grub_mdraid_detect): Likewise.
	* grub-core/disk/raid.c (insert_array): Automatically reallocate
	members.
	* include/grub/raid.h (grub_raid_member): New struct.
	(grub_raid_array): Transform devices and start_sector into usage of
	grub_raid_member. All users updated
	(allocated_devs): New member.