Added another potential replacement for MPI_Reduce_scatter_block.
Added another potential replacement for MPI_Reduce_scatter_block.

ahmadia/elemental,birm/Elemental,mcopik/Elemental,sg0/Elemental,ahmadia/elemental,justusc/Elemental,justusc/Elemental,ahmadia/elemental,sg0/Elemental,sg0/Elemental,mcopik/Elemental,mcopik/Elemental,justusc/Elemental,mcopik/Elemental,sg0/Elemental,birm/Elemental,ahmadia/elemental,mcopik/Elemental,sg0/Elemental,birm/Elemental,justusc/Elemental,birm/Elemental,mcopik/Elemental,birm/Elemental,justusc/Elemental,birm/Elemental,sg0/Elemental,justusc/Elemental