Fortran use-mpi-tkr: remove real*16 and complex*32 (for now)

There is more comprehensive work regarding MPI_SIZEOF coming, but the
Fortran working group in the MPI Forum is debating this internally,
and I'm still doing more testing to get a final solution.  So for the
moment, just remove real*16 and complex*32 support so that it compiles
porperly with older compilers (that do not support real*16 and
complex*32).
Minor cleanup to node_stat packing routine
Fix potential issue if opal_hwloc_topology is NULL

cmr=v1.8.2:reviewer=jsquyres
Cleanup memory leak

cmr=v1.8.2:reviewer=hjelmn