Update curl request documentation to remove v2.0
Update curl request documentation to remove v2.0

The curl examples we keep in our documentation contain examples for
interacting with the now removed v2.0 APIs. This commit removes those
examples since we no long support v2.0, except for the ec2token API
until the T release. The curl examples didn't have any v2.0 ec2token
examples.

Change-Id: I7e16421873de1c2ebf13db971bef80a2d74e5823

openstack/keystone,mahak/keystone,mahak/keystone,openstack/keystone,mahak/keystone,openstack/keystone