Properly handle machines that have no variants
Properly handle machines that have no variants

Contributes to CURA-341

fieldOfView/Cura,hmflash/Cura,Curahelper/Cura,Curahelper/Cura,ynotstartups/Wanhao,senttech/Cura,fieldOfView/Cura,totalretribution/Cura,hmflash/Cura,totalretribution/Cura,senttech/Cura,ynotstartups/Wanhao