Set public and admin_endpoint in keystone.conf

The public_endpoint and admin_endpoint options should be set in
keystone.conf using get_access_endpoint. Otherwise, any services
issuing requests to http://10.0.0.1:5000/v2.0 will receive the
default endpoints (localhost) instead of the correct ones.

Fixes rcbops/chef-cookbooks#639
Merge pull request #152 from DavidWittman/639-conf-endpoints

Set public and admin_endpoint in keystone.conf