vchoi_fork

[svn-r2935] Purpose:
    Bug fix
Description:
    The optimized MPIO code was not working with the TFLOPS machine.
    It kept reporting "can't convert from size to size_i" errors in
    H5FD_mpio_write() and H5FD_mpio_read().
Solution:
    The error was actually in H5S_mpio_spaces_xfer() in H5Smpio.c
    in which the variable mpi_count was declared as size_t (only
    4 bytes big in TFLOPS) when it should be hsize_t (8 bytes big in TFLOPS).
    Corrected and also changed to use the (hsize_t) to case size_i in
    H5FD_mpio_write() and H5FD_mpio_read() since that is what it should
    be.
Platforms tested:
    TFLOPS and modi4 (-64, parallel)