Updates README.md

Updates description of README.md

Change-Id: Id611014648f3deb21d7cec445f5f0a802beba2fa
Merge branch 'master' of https://github.com/fengju/openstack-upgrade

Conflicts:
	README.md

Change-Id: I12a42af3eae72befad41c4a06feed90acb539f4e