This adds a few more things to the upgrade checks
reference docs after getting questions about it
during the Stein release goal implementation from
other project teams:
1. Notes the high level set of steps for upgrading
nova in grenade and where nova-status fits into
that sequence.
2. Links to the oslo.upgradecheck library which
didn't exist when the original document was
written.
3. Adds a FAQs section with Q&A for several things
that have come up during the Stein release goal.
Change-Id: I990e5dbe563fa342f7481c3720445b924447ad54
Story: 2003657
This adds some background, guidelines and structural
notes on writing nova-status upgrade checks.
This is intentionally written with some potentially
redundant information or nova developers as it's
also meant to be consumed outside nova as part of the
community-wide "upgrade-checkers" goal for Stein [1].
Story: 2003570
[1] https://governance.openstack.org/tc/goals/stein/upgrade-checkers.html
Change-Id: I340b25edeab3ac19c5d0bedfc69acd037d57bdd2
