Back branch update releases this week; beta postponed

In view of the recently-discovered data loss bug in pg_upgrade,
it seems imperative to push out update releases fixing that as soon
as possible. The core team has therefore decided to wrap back-branch
update releases this Thursday for release Monday 4/18.

We were previously targeting wrapping 9.1beta1 on Thursday, but it
would not be a good idea to do that at the same time as the update
releases. Aside from the risk of overburdening packagers, we would
like to make a PR splash for the beta release, and not dilute that
message with the update-releases-to-fix-data-loss issue. And with
assorted major contributors off at a conference this week, it was
far from clear that we'd be ready for beta by Thursday anyway.
Accordingly, the beta release will have to be postponed.

Since the following weekend is Easter holidays for many, it's not
very practical to consider a one-week slip for beta. The tentative
plan is to slip two weeks (ie, beta wrap will be April 28). We could
possibly do something creative with a midweek release date, but that
could be problematic from both packagers' and PR standpoints.

regards, tom lane