least 2009; change min to max of the bw/rbw values, since the link has to
satisfy the direction with the higher bandwidth not the lower bandwidth. We
probably don't run into this very often since people do not often do
asymmetric links like 100Mb/155Mb, on nodes that have both 1Gb and 100Mb
interfaces.

Also through in some warning code to catch this before it gets to snmpit,
which fails when you try to set a 100Mb interface to 1Gb. This might turn
into a fatal error later.