map-services: add openvswitch

OVS service is called:
 - openvswitch-switch on Debian/Ubuntu
 - openvswitch on RHEL/Fedora

This changes is needed to get the neutron element to work
on Debian/Ubuntu with systemd:
  I6e3df30dc3a6918f3a949a7dac47289ede5c3d1f

Change-Id: I2748a9db7f8ee456698187a9646bc7cda2256fe7
Merge "map-services: add openvswitch"