Improve comments in test_catalog
Improve comments in test_catalog

This patch is a continuation from;
I59c4478a30f22f103b1f498f566b7f955f9c8848

- Fix some grammar nits

- Replace v2 to v2.0

Co-Authored-By: Tony Wang <wwwjfy@gmail.com>

Change-Id: I77bfc9c8b0718cc8a12fd79c0ccedf2404ab6c41

openstack/keystone,himanshu-setia/keystone,rajalokan/keystone,openstack/keystone,mahak/keystone,mahak/keystone,cernops/keystone,ilay09/keystone,ilay09/keystone,rajalokan/keystone,dims/keystone,klmitch/keystone,dims/keystone,rajalokan/keystone,himanshu-setia/keystone,mahak/keystone,cernops/keystone,openstack/keystone,ilay09/keystone,klmitch/keystone