Add the new user and group for OpenvSwitch 2.8 version
Add the new user and group for OpenvSwitch 2.8 version

OvS2.8, by default in fedora/centos/rhel, run as openvswitch:openvswitch
and when DPDK is enabled, it runs as openvswitch:hugetlbfs. Adding the
new user and group to the config.

Change-Id: I674cbd45e17906448dd54acfdf7a7059880b7278

rahulunair/kolla,stackforge/kolla,openstack/kolla,rahulunair/kolla,stackforge/kolla,stackforge/kolla,openstack/kolla