Properly extract CPU speed in VCH creation handler

Because JSON and Go have different models for inheritance, properly
interpreting the structure of the API parameters can be confusing.

In this case, we need to reference the nested units variable from
the "subclass" instead of the units variable in the parent, which
will always have its zero value (the empty string).

lib/apiservers/service/restapi/handlers/vch_create.go

@@ -564,7 +564,7 @@ func mhzFromValueHertz(m *models.ValueHertz) *int {
 	v := float64(m.Value.Value)
 
 	var mhzs float64
-	switch m.Units {
+	switch m.Value.Units {
 	case models.ValueHertzUnitsHz:
 		mhzs = v / float64(units.MB)
 	case models.ValueHertzUnitsKHz: