Update openstack.rst
Update openstack.rst

make it clearer that first bullet sets are separate options not four combined requirements
beddari/calico,matthewdupre/felix,neiljerram/felix,kasisnu/calico,beddari/calico,anortef/calico,kasisnu/calico,neiljerram/felix,alexhersh/calico,Metaswitch/calico,neiljerram/felix,TrimBiggs/calico,Metaswitch/calico,ocadotechnology/calico,ocadotechnology/calico,alexhersh/calico,TrimBiggs/calico,neiljerram/felix,anortef/calico,matthewdupre/felix