Per change I97215e94efdd8c05045872fb9ba7d2089dc6efb8, nova
does not perform version discovery or try to deal with backlevel
placement versions, and the upgrade docs say that placement needs
to be upgraded before upgrading any nova services. Because of
this assertion, we can remove the per-release nova-scheduler-specific
note in the placement upgrade notes for Rocky because while it's
accurate for the nova-scheduler service, it might not be accurate
for the nova-api, nova-conductor or nova-compute services which
also use placement. So the best guidance is to just globally say
that placement must be upgraded before *any* nova services, which
our upgrade doc already says.
Change-Id: I8bf6ab049f15ad24a5fbf0557bd0cd8652101901
Matt Riedemann
dc6cb06021