pg_createcluster not obeying default for socket directory

Hi,

Just installed 9.3b2 from the PG group's APT repository. Because I'm
upgrading from 9.3b1 I need to recreate my cluster.

I get this warning when creating the cluster:

colin(at)corundum:~$ sudo pg_createcluster 9.3 main --start
Creating new cluster 9.3/main ...
config /etc/postgresql/9.3/main
data /var/lib/postgresql/9.3/main
locale en_US.UTF-8
Warning: The socket directory for owners other than 'postgres'
defaults to /tmp. You might want to change the unix_socket_directories parameter
in postgresql.conf to a more secure directory.
port 5432
colin(at)corundum:~$

Yet, acccording to pg_createcluster when run with no arguments,

colin(at)corundum:~$ pg_createcluster
Usage: /usr/bin/pg_createcluster [options] <version> <cluster name>
[-- <initdb options>]

Options:
-s <dir> socket directory (default: /var/run/postgresql for clusters
owned by 'postgres', /tmp for other clusters)

[other options snipped]

This seems like a bug to me. I checked -- my cluster is owned by
'postgres' as is the default.

Cheers,

Colin