cinder/rbd: return more info on errors
cinder/rbd: return more info on errors

Signed-off-by: Peng Tao <39d8af57313740070ea49547576f55682fe5221a@gmail.com>

hyperhq/hypernetes,hyperhq/hypernetes,hyperhq/hypernetes,hyperhq/hypernetes,hyperhq/hypernetes