We had inconsistent service upgrade order information in our upgrade
documentation. This corrects the order to be consistent with our
recommended order of operations.
Change-Id: Ifa8ea98e494d3058ef1a29fee4ab9fa76149ce08
Closes-bug: #1738223
One of the requirements to achieve assert:supports-rolling-upgrade TC
tag is to provide a "plan that allows operators to roll out new code to
subsets of services, eliminating the need to restart all services on new
code simultaneously".
This commit documents such rolling upgrade procedure in the devref,
which is last outstanding requirement for Cinder.
Change-Id: I562deafcd4bb9f5666cc35ae77a6bf20ab889612
