vchoi_fork

[svn-r12725] Purpose:
Bug Fix (Bug 544)

Description:
SGI Altix's MPI_File_get_size overflowed at 2GB and more.
Put in a temporary patch to use stat() instead to make Cobalt
passing on this test (bigdset).  A better fix (like detect if
MPI_File_get_size does not work before using this is preferred.)

Tested:
Cobalt and Heping.