fix S/R SCALPROD : when n=sNx*sNy was not multiple of 5, was dropping the  first (up to 4) elements of the vector product.
fix S/R SCALPROD : when n=sNx*sNy was not multiple of 5, was dropping the
 first (up to 4) elements of the vector product.

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