updated intro text- 564

resolves: https://github.com/ClusterHQ/flocker/issues/564
I'm not sure if we have a standard for bulleted lists (or if there is a known best-practice) but I noticed that this is different to the capitalisation used in https://docs.clusterhq.com/en/0.1.0/gettingstarted/tutorial/vagrant-setup.html#requirements for example.