Session Cache is not configured - Phusion Passenger

Got this error in the Apache error log while trying to setup Ruby on Rails app with Phusion Passenger on Mac OS X:

[Wed Jul 15 14:26:07 2009] [notice] caught SIGTERM, shutting down
[Wed Jul 15 14:26:07 2009] [warn] Init: Session Cache is not configured [hint: SSLSessionCache]

Apache errors seem obtusely opaque.
Found the fix in this blog entry:
http://benr75.com/2008/04/12/setup-mod_rails-phusion-mac-os-x-leopard
The RailsEnv entry needs to be set correctly in the Apache httpd.conf VirtualHost element, like so:

<VirtualHost *>
  ServerName app.test
  DocumentRoot /Users/benr/Rails/app/public
  RailsEnv development
</VirtualHost>

ServerName can be 'localhost' if you are running locally for development/testing.