Remove VoxelType construction from SIFT::ModelBase functors
Remove VoxelType construction from SIFT::ModelBase functors

Suspect this was the intention of commit 619a9318

MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3