dwifslpreproc: Remove eddy_quad attempt with explicit Python3
dwifslpreproc: Remove eddy_quad attempt with explicit Python3

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