Correct normal response codes for v2.0 versions doc
Correct normal response codes for v2.0 versions doc

20X and 30X http status codes don't represent errors.

Change-Id: I8a6809f89391e0cf4b59ffc5aa14607fee01c8a6

cernops/keystone,rajalokan/keystone,openstack/keystone,rajalokan/keystone,ilay09/keystone,mahak/keystone,ilay09/keystone,cernops/keystone,rajalokan/keystone,openstack/keystone,openstack/keystone,mahak/keystone,mahak/keystone,ilay09/keystone