*****   THIS INCLUDES A SMALL CHANGE IN THE MPI-RTE INTERFACE   *****

Fix two problems that surfaced when using direct launch under SLURM:

1. locally store our own data because some BTLs want to retrieve 
   it during add_procs rather than use what they have internally

2. cleanup MPI_Abort so it correctly passes the error status all
   the way down to the actual exit. When someone implemented the
   "abort_peers" API, they left out the error status. So we lost
   it at that point and *always* exited with a status of 1. This 
   forces a change to the API to include the status.

cmr:v1.7.3:reviewer=jsquyres:subject=Fix MPI_Abort and modex_recv for direct launch