remove "usingSphericalPolarMterms" that was not always initialized,    and with no equivalent for other grids (e.g.: CylindricalGrid).
remove "usingSphericalPolarMterms" that was not always initialized,
   and with no equivalent for other grids (e.g.: CylindricalGrid).

altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h