HA heartbeat traffic set to the same priority level as data traffic

Local out traffic, including HA heartbeat traffic, is now set to high priority to make sure it is processed at the same priority level as data traffic. This change has been made because HA heartbeat traffic can be processed by NP6 processors that are also processing data traffic. When HA heartbeat traffic was set to a lower priority it may have be delayed or dropped by very busy NP6 processors resulting in HA failovers.