Since blueprint return-alternate-hosts in Queens, the scheduler
returns a primary selected host and some alternate hosts based
on the max_attempts config option. The only reschedules we have
are during server create and resize/cold migrate. The list of
alternative hosts are passed down from conductor through compute
and back to conductor on reschedule and if conductor gets a list
of alternate hosts on reschedule it will not call the scheduler
again. This means the RetryFilter is effectively useless now since
it shouldn't ever filter out hosts on the first schedule attempt
and because we're using alternates for reschedules, we shouldn't
go back to the scheduler on a reschedule. As a result this change
deprecates the RetryFilter and removes it from the default list
of enabled filters.
Change-Id: Ic0a03e89903bf925638fa26cca3dac7db710dca3
Matt Riedemann
257ef9573f