* disk/ata.c (grub_ata_open): Don't lose precision in disk->id.
* disk/host.c (grub_host_open): Likewise.
* disk/loopback.c (grub_loopback_open): Likewise.
* disk/memdisk.c (grub_memdisk_open): Use a string pointer for
disk->id as in disk/host.c, not a multi-character constant.
* disk/host.c (grub_host_open): Remove attribute unused from
name parameter. Add check for "host". This fixes the problem
that grub-emu does not find partitions.
