tckglobal: Fix out-of-bounds issue introduced with the new row method.
tckglobal: Fix out-of-bounds issue introduced with the new row method.

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