vchoi_fork

[svn-r4997] Purpose:
	Bug Fix
Description:
	So, for Raw I/O in parallel, if you open a file with truncation by
	multiple processes, it looks as if one process could open the file
	and start writing to it while another process also opens the file
	with truncation, thus wiping out all of the stuff the first process
	wrote to the file.

	This is bad.

	Also added some garbage collection to the pio_perf routine to reclaim
	the space taken by some of the tables.
Solution:
	Placed an MPI_Barrier() statement after the Raw open()/create() call
	so that all processes are synced up before they start writing to the
	file.

	Added free() calls to the tables which weren't being free'd.
Platforms tested:
	Linux-pp (eirene)