Fix README instructions
Fix README instructions

* uploading results anonymously is no longer supported, so the
patch removes related instructions from README
* tempest results are no longer stored under .tempest/.testrepository,
however, they are stored under .tempest/.stestr as Tempest has switched
to stestr a while ago.

Change-Id: I22f5bd36d5d275ca4e283afbc3af5cce949026f4

openstack/refstack-client,stackforge/refstack-client,openstack/refstack-client,stackforge/refstack-client