I'm getting lots of 500 errors when trying to get to test logs
via URLs like this:
    https://ubercautotest.corp.google.com/tko/retrieve_logs.cgi?job=/results/204247244-chromeos-test/chromeos6-row2-rack11-host20/

Those URLs are supposed to forward to a Stainless URL like this:
    https://stainless.corp.google.com/browse/chromeos-autotest-results/204247244-chromeos-test/chromeos6-row2-rack11-host20/

The stainless URL works on its own:  The 500 failures are apparently on
the cautotest side when trying to send the redirect.

The errors happen more often that not, but they don't fail 100% of the
time, so I don't think the problem is merely an error in the configuration
file.