Update Tempest README file
Update Tempest README file

This patch just improves the text in the tempest README.

Change-Id: Ie813b48fe097c1cdf0027c58c198dca36ebf7292

ekcs/congress,openstack/congress,ramineni/my_congress,ekcs/congress,ekcs/congress,ramineni/my_congress,ramineni/my_congress,openstack/congress,ekcs/congress,ramineni/my_congress