Switch quantum -> neutron in the README.md
Switch quantum -> neutron in the README.md

Change-Id: Ib0248de0145b197001ac47463f6d4cbbb409637d

openstack/tripleo-image-elements,openstack/tripleo-image-elements,radez/tripleo-image-elements,radez/tripleo-image-elements,rdo-management/tripleo-image-elements,rdo-management/tripleo-image-elements