ovs_events: change configuration option defaults

Right now, the plugin dispatches values by default and doesn't send
any notification messages. The expected behaviour of the event plugin
is to send notification by default. So, changed default value of
SendNotification & DispatchValues options to opposite.

Change-Id: I908799da1b2e75d2089765769ce56af00246c440
Signed-off-by: Mytnyk, VolodymyrX <volodymyrx.mytnyk@intel.com>