[OMPI users] MPI hangs on poll_device() with rdma

[Eva]

Run MPI_Send on MPI1.8.5 without multithread enabled:
it hangs on mca_pml_ob1_send() -> opal_progreses() ->
btl_openib_component_progress() -> poll_device() -> libmlx4-rdmav2.so -> cq
-> phread_spin_unlock
The program can run on TCP with no error.