Removed auth creds from paste files

The paste files do not need auth creds.  Only required in the
`[keystone_authtoken]` section of the api and registry configs.
Also added `delay_auth_decision` to [filter:authtoken] to match
upstream configs.

See:
https://github.com/stackforge/cookbook-openstack-image/blob/master/templates/default/glance-api-paste.ini.erb
https://github.com/stackforge/cookbook-openstack-image/blob/master/templates/default/glance-registry-paste.ini.erb