vcsim/*: Fix Errors unhandled issues
vcsim/*: Fix Errors unhandled issues

See,
$ gometalinter --vendor --disable-all --enable=gosec --deadline 10m ./vcsim/...
vcsim/main.go:116::warning: Errors unhandled.,LOW,HIGH (gosec)
vcsim/main.go:200::warning: Errors unhandled.,LOW,HIGH (gosec)

bruceadowns/govmomi,bruceadowns/govmomi,vmware/govmomi,vmware/govmomi,vmware/govmomi,bruceadowns/govmomi