Fix the bug introduced into the concentric infill in #90
Fix the bug introduced into the concentric infill in #90

daid/CuraCutEngine,uus169/CuraEngine,foosel/CuraEngine,pratikshashroff/pcura,pratikshashroff/pcura,totalretribution/CuraEngine,pratikshashroff/pcura,phonyphonecall/CuraEngine,be3d/CuraEngine,jacobdai/CuraEngine-1,Ultimaker/CuraEngine,electrocbd/CuraEngine,ROBO3D/CuraEngine,uus169/CuraEngine,alephobjects/CuraEngine,Jwis921/PersonalCuraEngine,markwal/CuraEngine,alephobjects/CuraEngine,ROBO3D/CuraEngine,be3d/CuraEngine,jacobdai/CuraEngine-1,mspark93/CuraEngine,derekhe/CuraEngine,derekhe/CuraEngine,patrick3coffee/CuraTinyG,foosel/CuraEngine,uus169/CuraEngine,electrocbd/CuraEngine,totalretribution/CuraEngine,Skeen/CuraJS-Engine,fxtentacle/CuraEngine,patrick3coffee/CuraTinyG,patrick3coffee/CuraTinyG,alex1818/CuraEngine,markwal/CuraEngine,markwal/CuraEngine,derekhe/CuraEngine,robotustra/curax,ROBO3D/CuraEngine,Ultimaker/CuraEngine,mspark93/CuraEngine,Skeen/CuraJS-Engine,phonyphonecall/CuraEngine,be3d/CuraEngine,daid/CuraCutEngine,phonyphonecall/CuraEngine,fxtentacle/CuraEngine,electrocbd/CuraEngine,fxtentacle/CuraEngine,Skeen/CuraJS-Engine,Jwis921/PersonalCuraEngine,alephobjects/CuraEngine,mspark93/CuraEngine,Jwis921/PersonalCuraEngine,alex1818/CuraEngine,robotustra/curax,alex1818/CuraEngine,totalretribution/CuraEngine,robotustra/curax,foosel/CuraEngine,jacobdai/CuraEngine-1