Do now recursively chown {{ install_lib_dir }}

Currently, we recursively chown /usr/local/lib/python2.7/dist-packages
to www-data:www-data.  This should be unnecessary as we can (and do)
chown individual directories in the horizon specific roles.

(cherry picked from commit a63180ae1ffa4e19a854e2aced53567e76e58cb9)

Closes issue #367