Add missing brackets
Add missing brackets

To comply to the code style.

Contributes to issue CURA-1911.

alephobjects/CuraEngine,ROBO3D/CuraEngine,ROBO3D/CuraEngine,ROBO3D/CuraEngine,Ultimaker/CuraEngine,totalretribution/CuraEngine,alephobjects/CuraEngine,alephobjects/CuraEngine,totalretribution/CuraEngine,totalretribution/CuraEngine,Ultimaker/CuraEngine