dist: Update NEWS for 3.1.0rc2

Signed-off-by: Brian Barrett <[email protected]>

Author: bwbarrett

NEWS

@@ -56,14 +56,16 @@ included in the vX.Y.Z section and be denoted as:
 3.1.0 -- January, 2018
 ----------------------
 
+- The output-filename option for mpirun is now converted to an
+  absolute path before being passed to other nodes.
 - Add monitoring component for PML, OSC, and COLL to track data
   movement of MPI applications.  See
   ompi/mca/commmon/monitoring/HowTo_pml_monitoring.tex for more
   information about the monitoring framework.
 - Add support for communicator assertions: mpi_assert_no_any_tag,
   mpi_assert_no_any_source, mpi_assert_exact_length, and
   mpi_assert_allow_overtaking.
-- Update PMIx to version 2.1.0.
+- Update PMIx to version 2.1.1.
 - Update hwloc to 1.11.7.
 - Many one-sided behavior fixes.
 - Improved performance for Reduce and Allreduce using Rabenseifner's algorithm.