when ports are changed, set both egress and untagged... a switch
reset/sets the untagged bit upon egress change...

The Lenovo's SNMP get is broken w/ multiple OIDs, so add a hack
to detect that the switch is a Lenovo, and don't use getmany (well
call getmany_real w/ one OID at a time).

This can be used to set the STP priority for the root switch..