Update Congress Tutorial - Tenant Sharing Policy

[Aimee Ukasick]

http://docs.openstack.org/developer/congress/tutorial-tenant-sharing.html

The tutorial is outdated.
1) step 11: get tenant IDs is incorrect for Identity v3; I believe the call should be openstack user list
2) step 12: command line call returns Syntax error for rule::Literal nova:servers(device_id, name2, c2, d2, tenant_id2, f2, g2, h2) contained 8 arguments but only 10 arguments are permitted

I stopped after step 12. The whole tutorial needs to be reviewed and updated.