volume identification: abolish /proc/partitions and /proc/cdroms

volume identification: abolish /proc/partitions and /proc/cdroms
scanning. It does not catch volume managers and such.
Adding even more cruft is bad, so I decided to simply
scan /dev/* for any block devices. See how much better
it finds devices now:

# ./busybox_old blkid
/dev/sda1: LABEL="/boot" UUID="7931e231-dcb4-4b6d-9301-f7354ae24061"
/dev/dm-0: LABEL="Fedora-9-Live-x8" UUID="bb491e1e-1145-4f5b-b0ab-cbd2baf4f15a"
/dev/dm-1: UUID="edc2a920-ef83-437e-ba64-d3b6dc851267"
/dev/sdb1: UUID="6F84-ED0F"

# ./busybox blkid
/dev/sdb1: UUID="6F84-ED0F"
/dev/root: LABEL="Fedora-9-Live-x8" UUID="bb491e1e-1145-4f5b-b0ab-cbd2baf4f15a"
/dev/dm-1: UUID="edc2a920-ef83-437e-ba64-d3b6dc851267"
/dev/dm-0: LABEL="Fedora-9-Live-x8" UUID="bb491e1e-1145-4f5b-b0ab-cbd2baf4f15a"
/dev/sda1: LABEL="/boot" UUID="7931e231-dcb4-4b6d-9301-f7354ae24061"
/dev/mapper/VolGroup00-LogVol01: UUID="edc2a920-ef83-437e-ba64-d3b6dc851267"
/dev/mapper/VolGroup00-LogVol00: LABEL="Fedora-9-Live-x8" UUID="bb491e1e-1145-4f5b-b0ab-cbd2baf4f15a"

function                                             old     new   delta
static.drive_name_string                              12       -     -12
append_mount_options                                 205     190     -15
volume_id_open_node                                   37      18     -19
uuidcache_check_device                               485     257    -228
uuidcache_init                                       637      36    -601
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 0/4 up/down: 0/-875)           Total: -875 bytes
   text    data     bss     dec     hex filename
 792218     592    6648  799458   c32e2 busybox_old
 791260     592    6648  798500   c2f24 busybox_unstripped