Set pypi-server to cache and use known built wheels

The pypi server is able to use our existing built wheels. Because
the pypi-server recursivly scans the provided directory, all wheels
for from any source can be fed into the server making it a universal
solution for serving python packages; no matter the distro or 
archetecture.

To ensure system performance the pypi-server package has been changed to
include  the optional cache functionality it provides. As noted in the 
server docs,  enabling caching will greatly improve performance when 
serving thousands of packages.

> The documentation for pypi-server is all contained within the
  application, use `pypi-server -h`. That said, under bullet point 4,
  here - https://pypi.python.org/pypi/pypiserver#table-of-contents -
  an online copy exists.

Change-Id: Icc2ee264fc213b258642b5393dd78b1b26ef0542
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

defaults/main.yml

@@ -76,11 +76,11 @@ repo_requires_pip_packages:
 
 # Set the list of packages for the pypiserver
 repo_pypiserver_pip_packages:
- - "pypiserver==1.2.0"
+ - "pypiserver[cache]==1.2.0"
 
 # Set the path to place all built python wheels
 # This is used by pypiserver to serve them
-repo_pypiserver_package_path: "{{ repo_service_home_folder }}/repo/python_packages"
+repo_pypiserver_package_path: "{{ repo_service_home_folder }}/pools"
 
 # Path to the pypiserver python virtualenv binaries
 repo_pypiserver_bin: "/openstack/venvs/pypiserver-1.2.0/bin"
@@ -109,4 +109,3 @@ repo_nginx_pypi_upstream: "pypi.python.org:443"
 # for up to 1 month
 repo_nginx_proxy_cache_path: >-
   /var/lib/nginx/pypi levels=1:2 keys_zone=pypi:16m inactive=1M max_size=1G
-