added forgotten Lock.h (CURA-3339)
added forgotten Lock.h (CURA-3339)

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