9.5 branching?

The postgresql repository has branched of the REL9_5_STABLE branch.  For
the time being, the "9.5" branch in the messages repository is still master.

I was wondering, would it be easier if we also branched off
REL9_5_STABLE in messages right now?

We could just ignore the master branch for now and later on fork it off
REL9_5_STABLE (instead of the other way around, which is what we'd
usually do).

(We could also blow away the master branch altogether and recreate it
later, but I don't know what that would do to new checkouts in the
meantime, because we don't have access to set the default branch on the
git.postgresql.org hosting.)