vchoi_fork

[svn-r12534] Purpose:
Bug fixes.

Description:
There were MPI_init and MPI_finalize calls in the code of h5tools_fopen in
parallel mode.  But if a non-MPI tool is invoke to open a non-existing
file, it tries to open the non-existing file with different VFD and
eventaully came to try with the MPIO or the MPIPOSIX vfd, then it would
try to do MPI_Init which would fail in the MPI environment if the a.out
was not launched by MPI properly.

Solution:
MPI_Init and MPI_Finalize in general should be called by the MPI application,
not called by a library subroutine as in the manner that was done here.
Removed the MPI_init and MPI_Finalize calls.  Used MPI_Initialized to
verify if this has been launched as an MPI application in the proper
manner before attempting to use the MPIO or the MPIPOSIX VFD to open
the file.

Tested:
In tg-ncsa parallel, where it had failed explicitly and also in Heping,
using both serial and parallel mode.