This patch adds two RewriteCond with backreferences which
check for the existence of an AFS-style split directory. If
the directory exists, the rewrite rule will apply the necessary
path changes.
This patch permits passthrough of files such as index.html
at the root directory, while not impacting the folder structure
at sub-directory levels.
This patch will break rather badly if pypi ever publishes a
package named 'index.html'.
Change-Id: I712f2d4e262b9e20378365af8173066522e2e0cd
137b185079