Pass NULL pointer as second argument to realpath

[thecopy]

Pass NULL pointer as second argument to realpath. Avoids buffer overflow error. This is standard behavior as of POSIX 2008

Running on Ubuntu AWS EC2, same error on my local WS Ubuntu:

IOR-2.10.3: MPI Coordinated Test of Parallel I/O

Run began: Tue Jun 23 10:50:08 2015
Command line used: ./IOR -f N8TrinityScript
Machine: Linux ip-172-30-0-114 3.13.0-48-generic #80-Ubuntu SMP Thu Mar 12 11:16:15 UTC 2015 x86_64
Using synchronized MPI timer
Start time skew across all tasks: 0.00 sec
*** buffer overflow detected ***: ./IOR terminated
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x7338f)[0x7f3c9ecc738f]
/lib/x86_64-linux-gnu/libc.so.6(__fortify_fail+0x5c)[0x7f3c9ed5ec9c]
/lib/x86_64-linux-gnu/libc.so.6(+0x109b60)[0x7f3c9ed5db60]
/lib/x86_64-linux-gnu/libc.so.6(+0x10a0f4)[0x7f3c9ed5e0f4]
./IOR[0x40f612]
....

Where ./IOR[0x40f612] points to the changed line in utilities.c.

[johnbent]

This repo has been orphaned. Please switch to use the only currently active IOR repo:
https://github.com/IOR-LANL/ior