dog: revert the change for output of "dog vdi list" manually

This patch is a temporal thing. The previous commit (ae3c78b9651cc2)
introduced change of "dog vdi list" command, it added a new field of
block size shift.

It breaks existing tests/fucntional. So this patch remove the
change. After the tests updated correctly, this patch can be reverted
simply.

Cc: Teruaki Ishizaki <ishizaki.teruaki@lab.ntt.co.jp>
Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>