Fix for /personfinder-prefixed static files. (#673)
Fix for /personfinder-prefixed static files. (#673)

In prod, we serve off google.org/personfinder, and the URL prefix isn't
stripped on its way to App Engine. I forgot to account for that when I
set up the fixed static file handling in PR #670.
google/personfinder,google/personfinder,google/personfinder,google/personfinder