Updated openstack/openstack
Project: openstack/stevedore  e8e9ca1e964963f7cb3db9eec62a7adeef2446a1

Fix incorrect image reference in documentation

Link to the correct image for the "API Enforcement" section of the PyCon
2013 essay.

Change-Id: I844e6dcd2dccd9367cc5c49f13b9abfc01b69f4b