Fix default network in NetworkFlag
Fix default network in NetworkFlag

Switch to higher-level govmomi types and use their Name() method,
rather than flag.name which is only set when -net flag is given.

excilsploft/govmomi,daxgames/govmomi,jrmycanady/govmomi,juju/govmomi,l1jiang/govmomi,vmware/govmomi,mevansam/vsphere-govmomi,frapposelli/govmomi,austinlparker/govmomi,ilikejam/govmomi,casualjim/govmomi,gonkulator/govmomi,anexia-it/govmomi,chrislovecnm/govmomi,caglar10ur/govmomi,juju/govmomi,bruceadowns/govmomi,runner-mei/govmomi,bruceadowns/govmomi,RotatingFans/govmomi,juju/govmomi,dougm/govmomi,logankimmel/govmomi,tkak/govmomi,ilikejam/govmomi,egorovv/govmomi,kristinn/govmomi,RotatingFans/govmomi,egorovv/govmomi,jrmycanady/govmomi,kristinn/govmomi,cgtexmex/govmomi,jrmycanady/govmomi,vmware/govmomi,abathla/govmomi,higebu/govmomi,tkak/govmomi,mevansam/vsphere-govmomi,abathla/govmomi,gonkulator/govmomi,caglar10ur/govmomi,austinlparker/govmomi,daxgames/govmomi,kristinn/govmomi,ilikejam/govmomi,anexia-it/govmomi,pietern/govmomi,caglar10ur/govmomi,mevansam/vsphere-govmomi,gonkulator/govmomi,dougm/govmomi,bruceadowns/govmomi,RotatingFans/govmomi,pietern/govmomi,casualjim/govmomi,excilsploft/govmomi,excilsploft/govmomi,l1jiang/govmomi,casualjim/govmomi,vmware/govmomi,cgtexmex/govmomi,abathla/govmomi,pietern/govmomi,tkak/govmomi,l1jiang/govmomi,chrislovecnm/govmomi,egorovv/govmomi,dougm/govmomi,logankimmel/govmomi,austinlparker/govmomi,chrislovecnm/govmomi,higebu/govmomi,higebu/govmomi,anexia-it/govmomi,runner-mei/govmomi,daxgames/govmomi,frapposelli/govmomi,logankimmel/govmomi,runner-mei/govmomi,frapposelli/govmomi,cgtexmex/govmomi