btrfs-progs: replace blkid_probe_get_wholedisk_devno

btrfs-progs: replace blkid_probe_get_wholedisk_devno

blkid_probe_get_wholedisk_devno() isn't available in some older
versions of libblkid.  It was used to work around an old
bug in blkid_devno_to_wholedisk(), but that has been fixed since
5cd0823 libblkid: fix blkid_devno_to_wholedisk(), present in
util-linux 2.17 and beyond.

If we happen to be missing that fix, the worst that happens is
that we'd fail to detect that a device is an ssd; the upside is
that this code compiles on older systems.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>