Revert "changing MPI_Reduce to MPI_Ireduce in Distributor"
Revert "changing MPI_Reduce to MPI_Ireduce in Distributor"

This reverts commit 7a21ca8a13f7ec5dc1e3a0e3a5e12e5a4655bfcd.

ORNL-CEES/DataTransferKit,dalg24/DataTransferKit,amccaskey/DataTransferKit,dalg24/DataTransferKit,dalg24/DataTransferKit,amccaskey/DataTransferKit,ORNL-CEES/DataTransferKit,Rombur/DataTransferKit,Rombur/DataTransferKit,dalg24/DataTransferKit,ORNL-CEES/DataTransferKit,amccaskey/DataTransferKit,amccaskey/DataTransferKit,ORNL-CEES/DataTransferKit,Rombur/DataTransferKit,Rombur/DataTransferKit