[Cosmo] cosmo-demo has "we're down" page now

[Jared Rhine]

I added a custom 502 error-handling page to the proxy configuration on
halua.  So now it will show a polite "the sharing service is down" page
instead of something ugly.  Assuming the box and apache is running, of
course.

-- 
Jared Rhine <jared at wordzoo.com>