'Return OVS version'

@staticmethod
def getOvsVersion():

    outp = quietRun('ovs-vsctl    --version')
    r = 'ovs-vsctl    \\(Open    vSwitch\\)    (.*)'
    m = re.search(r, outp)
    if (m is None):
        warn('Version    check    failed')
        return None
    else:
        info(('Open    vSwitch    version    is    ' + m.group(1)), '\n')
        return m.group(1)
