Update to MPICH2 1.3.1

Changes in 1.3.1

# OVERALL: MPICH2 is now fully compliant with the CIFTS FTB standard
  MPI events (based on the draft standard).

# OVERALL: Major improvements to RMA performance for long lists of
  RMA operations.

# OVERALL: Performance improvements for Group_translate_ranks.

# COLLECTIVES: Collective algorithm selection thresholds can now be controlled
  at runtime via environment variables.

# ROMIO: PVFS error codes are now mapped to MPI error codes.

# Several other minor bug fixes, memory leak fixes, and code cleanup.
  A full list of changes is available using:

    svn log -r7350:HEAD https://svn.mcs.anl.gov/repos/mpi/mpich2/tags/release/mpich2-1.3.1

    ... or at the following link:

    https://trac.mcs.anl.gov/projects/mpich2/log/mpich2/tags/release/mpich2-1.3.1?action=follow_copy&rev=HEAD&stop_rev=7350&mode=follow_copy

Changes in 1.3

# OVERALL: Initial support for fine-grained threading in
  ch3:nemesis:tcp.

# OVERALL: Support for Asynchronous Communication Progress.

# OVERALL: The ssm and shm channels have been removed.

# OVERALL: Checkpoint/restart support using BLCR.

# OVERALL: Improved tolerance to process and communication failures
  when error handler is set to MPI_ERRORS_RETURN.  If a communication
  operation fails (e.g., due to a process failure) MPICH2 will return
  an error, and further communication to that process is not
  possible.  However, communication with other processes will still
  proceed normally.  Note, however, that the behavior collective
  operations on communicators containing the failed process is
  undefined, and may give incorrect results or hang some processes.

# OVERALL: Experimental support for inter-library dependencies.

# PM/PMI: Hydra is now the default process management framework
  replacing MPD.

# PM/PMI: Added dynamic process support for Hydra.

# PM/PMI: Added support for LSF, SGE and POE in Hydra.

# PM/PMI: Added support for CPU and memory/cache topology aware
  process-core binding.

# DEBUGGER: Improved support and bug fixes in the Totalview support.

# Build system: Replaced F90/F90FLAGS by FC/FCFLAGS. F90/F90FLAGS are
  not longer supported in the configure.

# Multi-compiler support: On systems where C compiler that is used to
  build mpich2 libraries supports multiple weak symbols and multiple aliases,
  the Fortran binding built in the mpich2 libraries can handle different
  Fortran compilers (than the one used to build mpich2).  Details in README.

# Several other minor bug fixes, memory leak fixes, and code cleanup.
  A full list of changes is available using:

    svn log -r5762:HEAD https://svn.mcs.anl.gov/repos/mpi/mpich2/tags/release/mpich2-1.3

    ... or at the following link:

    https://trac.mcs.anl.gov/projects/mpich2/log/mpich2/tags/release/mpich2-1.3?action=follow_copy&rev=HEAD&stop_rev=5762&mode=follow_copy

(asau)