Install Guide: Object -> Block Storage for cinder

Fix wrong name

Change-Id: I7edab749ede77591e35bc00902ac8e33893923ed
Backport: havana
Closes-Bug: 1249164
(cherry picked from commit fc3e62731485d8b2881035fdbefc3a31af203854)
Merge "Install Guide: Object -> Block Storage for cinder" into stable/havana