Update Get API version Curl example
Update Get API version Curl example

Currently, `curl http://0.0.0.0:35357` and `curl http://0.0.0.0:35357/v2.0/`
no longer have the same response, since keystone has it's V3 APIs. Update
the doc to differentiate the two Curl example.

Change-Id: I08f5e3bd502ebd78ea775ea4135b5c3ffb80e9c7

ilay09/keystone,cernops/keystone,jumpstarter-io/keystone,vivekdhayaal/keystone,rajalokan/keystone,rajalokan/keystone,dstanek/keystone,jumpstarter-io/keystone,takeshineshiro/keystone,himanshu-setia/keystone,ilay09/keystone,jonnary/keystone,dstanek/keystone,ajayaa/keystone,mahak/keystone,vivekdhayaal/keystone,roopali8/keystone,klmitch/keystone,dims/keystone,mahak/keystone,idjaw/keystone,jumpstarter-io/keystone,dstanek/keystone,jonnary/keystone,dims/keystone,mahak/keystone,jamielennox/keystone,idjaw/keystone,cernops/keystone,rajalokan/keystone,openstack/keystone,takeshineshiro/keystone,openstack/keystone,jamielennox/keystone,klmitch/keystone,himanshu-setia/keystone,roopali8/keystone,maestro-hybrid-cloud/keystone,maestro-hybrid-cloud/keystone,ajayaa/keystone,vivekdhayaal/keystone,openstack/keystone,ilay09/keystone