MPI_Finalize slow with CUDA + OpenMPI 2.x (known OpenMPI issue; fixed in 3.1)

Created by: mhoemmen

Tpetra::CrsMatrix UnitTests2 takes > 560s in a CUDA 8 release build on K80. Seriously, what's going on? Do I need different KOKKOS_ARCH settings? It sure would have been nice to have had some performance tracking so we could have caught this. I don't think this is anything we did; we've only been fixing CUDA issues over time.

36/145 Test  #36: TpetraCore_CrsMatrix_UnitTests2_MPI_4 .......................................................   Passed  561.02 sec

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