When we abort during MPI_Init, we currently emit a totally incorrect error message stating that we were unable to aggregate error messages and cannot guarantee all other processes were killed. This simply isn't true IF the rte has been initialized.

So track that the rte has reached that point, and only emit the new message if it is accurate.

Note that we still generate a TON of output for a minor error:

Ralphs-iMac:examples rhc$ mpirun -n 3 -mca btl sm ./hello_c
--------------------------------------------------------------------------
At least one pair of MPI processes are unable to reach each other for
MPI communications.  This means that no Open MPI device has indicated
that it can be used to communicate between these processes.  This is
an error; Open MPI requires that all MPI processes be able to reach
each other.  This error can sometimes be the result of forgetting to
specify the "self" BTL.

  Process 1 ([[50239,1],2]) is on host: Ralphs-iMac
  Process 2 ([[50239,1],2]) is on host: Ralphs-iMac
  BTLs attempted: sm

Your MPI job is now going to abort; sorry.
--------------------------------------------------------------------------
*** An error occurred in MPI_Init
*** on a NULL communicator
*** MPI_ERRORS_ARE_FATAL (processes in this communicator will now abort,
***    and potentially your MPI job)
*** An error occurred in MPI_Init
*** on a NULL communicator
*** MPI_ERRORS_ARE_FATAL (processes in this communicator will now abort,
***    and potentially your MPI job)
*** An error occurred in MPI_Init
*** on a NULL communicator
*** MPI_ERRORS_ARE_FATAL (processes in this communicator will now abort,
***    and potentially your MPI job)
--------------------------------------------------------------------------
MPI_INIT has failed because at least one MPI process is unreachable
from another.  This *usually* means that an underlying communication
plugin -- such as a BTL or an MTL -- has either not loaded or not
allowed itself to be used.  Your MPI job will now abort.

You may wish to try to narrow down the problem;

 * Check the output of ompi_info to see which BTL/MTL plugins are
   available.
 * Run your application with MPI_THREAD_SINGLE.
 * Set the MCA parameter btl_base_verbose to 100 (or mtl_base_verbose,
   if using MTL-based communications) to see exactly which
   communication plugins were considered and/or discarded.
--------------------------------------------------------------------------
-------------------------------------------------------
Primary job  terminated normally, but 1 process returned
a non-zero exit code.. Per user-direction, the job has been aborted.
-------------------------------------------------------
--------------------------------------------------------------------------
mpirun detected that one or more processes exited with non-zero status, thus causing
the job to be terminated. The first process to do so was:

  Process name: [[50239,1],2]
  Exit code:    1
--------------------------------------------------------------------------
[Ralphs-iMac.local:23227] 2 more processes have sent help message help-mca-bml-r2.txt / unreachable proc
[Ralphs-iMac.local:23227] Set MCA parameter "orte_base_help_aggregate" to 0 to see all help / error messages
[Ralphs-iMac.local:23227] 2 more processes have sent help message help-mpi-runtime / mpi_init:startup:pml-add-procs-fail
Ralphs-iMac:examples rhc$ 

Hopefully, we can agree on a way to reduce this verbage!