Fix error in duplex link vtop generation, that has been there since at
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.